Is the atomic mass unit (amu) the same as the Dalton (Da)?

Answer: Yes—in modern usage, u (unified atomic mass unit), amu, and Da (Dalton) all refer to the same unit Historical context : Pre-1961 (ambiguous): "amu" could mean the oxygen-based physics scale (¹⁶O = 16) or chemistry scale (natural O = 16) These differed by ~0.03%, causing confusion 1961 unification : IUPAC/IUPAP adopted carbon-12 standard "u" (unified atomic mass unit) replaced ambiguous "amu" 1 u = 1/12 mass of ¹²C atom 1970s-1993 : "Dalton" (Da) proposed as an alternative name honoring John Dalton Gained popularity in biochemistry Today : u : Official name, preferred in chemistry and physics Da : Alternative name, preferred in biochemistry (especially kDa for proteins) amu : Informal, but understood to mean "u" in modern contexts Bottom line : 1 u = 1 Da = 1 amu (modern) — all identical

Why was Carbon-12 chosen as the standard for atomic mass?

Answer: Carbon-12 unified divergent physics and chemistry scales while being abundant, stable, and convenient Historical problem (pre-1961): Physicists used ¹⁶O = 16.0000 exactly (pure isotope) Chemists used natural oxygen = 16.0000 exactly (isotope mixture) Natural oxygen is 99.757% ¹⁶O, 0.038% ¹⁷O, 0.205% ¹⁸O Result : Two incompatible atomic mass scales differing by ~0.03% Carbon-12 advantages : 1. Unification : Resolved the physics-chemistry discrepancy with a single standard 2. Abundance : ¹²C comprises 98.89% of natural carbon (readily available) 3. Stability : Not radioactive (unlike ¹⁴C); doesn't decay 4. Integer mass : Defining ¹²C = 12 exactly gives a clean reference point 5. Chemical importance : Carbon is the basis of organic chemistry—central to life and synthetic compounds 6. Mass spectrometry : Carbon compounds are ubiquitous calibration standards 7. Convenience : Most atomic masses end up close to integers (approximately equal to mass number A) Alternative considered : Hydrogen was Dalton's original choice, but hydrogen's mass (1.008 u) isn't exactly 1, and hydrogen forms fewer compounds than carbon or oxygen. Result : Since 1961, all atomic weights worldwide are based on ¹²C = 12.0000 u (exact)

How does the atomic mass unit relate to Avogadro's number?

Answer: The atomic mass unit and Avogadro's number are defined such that mass in u equals molar mass in g/mol numerically The elegant relationship : Avogadro's constant : N_A = 6.022 140 76 × 10²³ mol⁻¹ (exact, as of 2019 SI redefinition) Atomic mass unit : 1 u = 1/12 the mass of one ¹²C atom Molar mass constant : M_u = 1 g/mol (by definition of the mole) Mathematical relationship : 1 u = 1 g / N_A Example : One carbon-12 atom: 12 u One mole of carbon-12 atoms: 12 g Number of atoms: 6.022 × 10²³ Practical consequence : To convert molecular mass (u) to grams, multiply by Avogadro's number: 1 water molecule: 18 u 1 mole of water: 18 g 18 g ÷ (6.022 × 10²³) = 2.99 × 10⁻²³ g per molecule ✓ Why this works : The definition of the mole (amount containing N_A entities) is coordinated with the definition of the atomic mass unit to make this numerical equality hold.

What is the difference between atomic mass and atomic weight?

Answer: Atomic mass refers to a specific isotope; atomic weight is the weighted average of all isotopes in natural abundance Atomic mass (isotope-specific): Mass of one specific isotope Example: ¹²C has atomic mass = 12.0000 u (exact) Example: ¹³C has atomic mass = 13.0034 u Atomic weight (element average): Weighted average of all naturally occurring isotopes Example: Natural carbon (98.89% ¹²C, 1.11% ¹³C) has atomic weight = 12.0107 u Listed on the periodic table Calculation for carbon : Atomic weight = (0.9889 × 12.0000) + (0.0111 × 13.0034) = 12.0107 u Why "weight" instead of "mass"? Historical naming; "atomic weight" actually refers to mass, not weight (force). The term persists despite being technically incorrect. Relative atomic mass : Modern term preferred over "atomic weight" (same meaning, less confusing) Important distinction : When doing precise isotope work (mass spectrometry, nuclear chemistry), use atomic masses of specific isotopes, not elemental atomic weights.

Can I use atomic mass units for objects larger than molecules?

Answer: Technically yes, but it's impractical—atomic mass units are too small for macroscopic objects Practical range for atomic mass units : Atoms : 1-300 u (hydrogen to heaviest elements) Small molecules : 10-1,000 u Proteins : 1,000-10,000,000 u (1 kDa - 10 MDa) Viruses : up to ~1,000 MDa (1 gigadalton, GDa) Beyond this : Use conventional mass units (grams, kilograms) Example (why it's impractical): A grain of sand (~1 mg = 10⁻⁶ kg) In atomic mass units: 10⁻⁶ kg ÷ (1.66 × 10⁻²⁷ kg/u) ≈ 6 × 10²⁰ u This number is unwieldy! Rule of thumb : Use atomic mass units for individual molecules or molecular complexes; switch to grams/kilograms for anything visible to the eye. Extreme example : A 70 kg human = 4.2 × 10²⁸ u (42,000 trillion trillion u—utterly impractical!)

How accurate are modern atomic mass measurements?

Answer: Extraordinarily accurate—often 8-10 decimal places (parts per billion precision) Modern mass spectrometry precision : Typical : 1 part per million (ppm) — 6 decimal places High-resolution : 1 part per billion (ppb) — 9 decimal places Ultra-high-resolution : 0.1 ppb — 10 decimal places Example: Carbon-12 : Defined as exactly 12.00000000000... u (infinite precision by definition) Example: Hydrogen-1 : Measured value: 1.00782503207 u (11 significant figures!) Uncertainty: ±0.00000000077 u Why such precision matters : 1. Isotope identification : Distinguishing ¹²C¹H₄ (16.0313 u) from ¹³C¹H₃ (16.0344 u) requires high precision 2. Mass defect measurements : Nuclear binding energies calculated from tiny mass differences (0.1% of nuclear mass) 3. Molecular formula determination : Mass spectrometry can distinguish C₁₃H₁₂ from C₁₂H₁₂O from C₁₁H₁₆N (all ~168 u) with sufficient precision 4. Fundamental physics : Testing mass-energy equivalence, searching for physics beyond the Standard Model Limitation : Even with extreme precision, natural isotopic variation (different ¹²C/¹³C ratios in different samples) limits practical accuracy to ~4-5 decimal places for most chemical applications.

Do protons and neutrons have exactly the same mass?

Answer: No—neutrons are slightly heavier than protons by about 0.14% Precise values : Proton mass : 1.007276466621 u Neutron mass : 1.00866491595 u Difference : 0.00138845 u (neutron is heavier by ~1.4 MeV/c²) Why this matters : 1. Neutron decay : Free neutrons decay into protons + electrons + antineutrinos with a half-life of ~10 minutes (neutron → proton + e⁻ + ν̄ₑ) 2. Nuclear stability : The mass difference affects which isotopes are stable vs. radioactive 3. Element synthesis : Mass differences determine which nuclear reactions can occur spontaneously in stars Fun fact : Both are close to 1 u (within 1%), which is why atomic mass numbers (protons + neutrons) approximately equal atomic masses in u Electron mass : Much lighter—only 0.000548580 u (~1/1836 of a proton) Consequence : Atomic mass is almost entirely due to protons and neutrons; electrons contribute negligibly (<0.03%)

Why is the atomic mass of hydrogen 1.008 u instead of 1 u?

Answer: Because protons are slightly heavier than 1/12 of a carbon-12 atom, plus hydrogen atoms include an electron Breakdown of hydrogen atom (¹H) : Proton: 1.007276 u Electron: 0.000549 u Binding energy (negligible): −0.000015 u Total : 1.007825 u ≈ 1.008 u Why isn't a proton exactly 1 u? The atomic mass unit is defined as 1/12 the mass of carbon-12, which contains 6 protons + 6 neutrons + 6 electrons, minus the nuclear binding energy: ¹²C mass: 12 u (exact) = 6 protons + 6 neutrons + 6 electrons − binding energy Solving: 1 nucleon (proton or neutron) ≈ 1.007-1.009 u (slightly more than 1 u) Why the carbon-12 nucleus is lighter than 12 individual nucleons : Nuclear binding energy (E = mc²) converts ~0.1 u of mass into energy that holds the nucleus together Result : Hydrogen (1 proton + 1 electron) ends up at 1.008 u, not 1.000 u

Will the definition of the atomic mass unit ever change?

Answer: Unlikely—the carbon-12 standard is stable, internationally accepted, and fundamental to chemistry Why it's stable : 1. International agreement : IUPAC, IUPAP, and NIST all recognize ¹²C standard (since 1961) 2. Infrastructure : All atomic weight tables, databases, lab equipment calibrated to carbon-12 3. No compelling alternative : Carbon-12 works perfectly for chemistry and biochemistry 4. Historical continuity : Changing standards disrupts 60+ years of data Recent change (2019 SI redefinition): The kilogram was redefined based on Planck's constant This indirectly affects the atomic mass unit (since 1 u is expressed in kg) But the change is at the 9th decimal place—completely negligible for chemistry Future refinement : Values like 1.660539066(50) × 10⁻²⁷ kg will get more decimal places as measurements improve, but the carbon-12 definition (1 u = 1/12 m(¹²C)) won't change Contrast with other standards : Meter: Redefined from physical bar to speed of light (1983) Kilogram: Redefined from physical cylinder to Planck constant (2019) Atomic mass unit: Based on fundamental particle (¹²C atom)—already a natural standard Conclusion : The carbon-12 definition is here to stay for the foreseeable future (decades to centuries).

1. How many milligrams are in a carat?

There are exactly 200 milligrams (mg) in 1 carat (ct) . This precise definition was adopted internationally in 1907 at the Fourth General Conference on Weights and Measures in Paris and has been the global standard ever since. The 200 mg figure was chosen because it was close to the average of various historical carat standards (which ranged from 188-215 mg across different regions) and because it creates a clean metric conversion: 5 carats = 1 gram . Modern gemological laboratories use precision electronic scales that can measure to 0.001 carat (0.2 mg) accuracy, ensuring consistent and transparent gem trade worldwide. For comparison, a US dollar bill weighs approximately 1 gram = 5 carats, and a paperclip weighs ~1 gram = 5 carats. The 200 mg standard is legally enforced by metrology institutes in all countries, making carat weight the most objective and reliable of the "Four Cs" of diamond grading.

2. How many grams are in a carat?

There are exactly 0.2 grams (g) in 1 carat (ct) , or conversely, 5 carats = 1 gram . This makes conversion straightforward: multiply carats by 0.2 to get grams, or multiply grams by 5 to get carats. Example: A 2.5-carat diamond weighs 2.5 × 0.2 = 0.5 grams (500 mg). The famous Hope Diamond (45.52 carats) weighs 45.52 × 0.2 = 9.104 grams . This clean metric relationship (5:1 ratio) was one reason the 200 mg standard was adopted in 1907—it integrates seamlessly with the metric system used globally in science and commerce. For context, a single M&M candy weighs approximately 1 gram = 5 carats, and a US nickel (5-cent coin) weighs 5 grams = 25 carats. The simplicity of the 5:1 carat-to-gram ratio facilitates international gem trade calculations and customs declarations.

3. Is carat the same as karat?

No, carat (ct) and karat (K or kt) are completely different units: Carat (ct) measures gemstone weight —1 ct = 200 mg. Used for diamonds, rubies, sapphires, emeralds, pearls, etc. Karat (K) measures gold purity —24K = 100% pure gold, 18K = 75% gold, 14K = 58.3% gold, etc. The fraction of pure gold is: (karat value ÷ 24). Example: 18K gold = 18/24 = 0.75 = 75% gold, 25% other metals (copper, silver, zinc for strength/color). Etymology : Both derive from the same root—"keration" (Greek for carob seed)—but diverged in meaning. In the US, different spellings distinguish them (carat/karat). In UK/Commonwealth, "carat" is used for both, distinguished by context and symbol (ct vs. K). Common example : "18-karat white gold engagement ring with a 1.5-carat diamond" correctly uses both units. Mixing them up causes confusion: "18-carat gold" is meaningless (gold purity isn't measured in gemstone weight units).

4. Why do diamonds cost more per carat as size increases?

Diamond prices exhibit exponential scaling —larger diamonds are disproportionately rarer, so price per carat increases with size. This is called the " carat premium ." Example pricing (excellent cut, G color, VS2 clarity): 0.50 ct: $2,000 total = $4,000/ct. 1.00 ct: $6,000 total = $6,000/ct (50% higher per-carat than 0.5 ct). 2.00 ct: $22,000 total = $11,000/ct (83% higher per-carat than 1 ct, 175% higher than 0.5 ct). Why? Rarity : Only ~1 in 1,000 rough diamonds yields a 1-carat polished diamond; only ~1 in 1 million yields 2+ carats. Mining yields mostly small stones. Psychological milestones : Whole carat sizes (1.0, 2.0, 3.0) are culturally significant, driving demand and premiums. Implication : A 2-ct diamond costs ~3-4× more than a 1-ct diamond of identical quality, not 2×. Conversely, buying slightly below milestones (0.90 ct instead of 1.0 ct) can save 15-20% with negligible visual difference.

5. What's the largest diamond ever found?

The largest gem-quality rough diamond ever discovered is the Cullinan Diamond , found on January 26, 1905, at the Premier Mine in Cullinan, South Africa. It weighed an astonishing 3,106.75 carats (621.35 grams, about 1.37 pounds)—roughly the size of a human fist. The diamond was presented to King Edward VII of the United Kingdom and was subsequently cut by Joseph Asscher & Co. in Amsterdam into 9 major gems and 96 smaller brilliants: Cullinan I ("Great Star of Africa"): 530.2 carats , the largest clear-cut diamond in the world, set in the British Royal Sceptre. Cullinan II ("Second Star of Africa"): 317.4 carats , set in the British Imperial State Crown. Both are part of the British Crown Jewels displayed in the Tower of London. Other large rough diamonds: Lesedi La Rona (2015, Botswana): 1,109 carats. Sewelô (2019, Botswana): 1,758 carats (second-largest ever). However, the largest cut and faceted diamond is the Golden Jubilee at 545.67 carats , owned by the Thai Royal Family.

6. Do all gemstones of the same carat weight look the same size?

No! Carat is weight, not size , and different gemstones have different densities (specific gravity), so the same carat weight yields different sizes: 1-carat diamond (SG 3.52): ~6.5 mm diameter (round brilliant). 1-carat ruby/sapphire (SG ~4.0, denser than diamond): ~6.0 mm diameter—looks smaller than diamond. 1-carat emerald (SG ~2.71, less dense than diamond): ~6.9 mm diameter—looks larger than diamond. 1-carat opal (SG ~2.15, much less dense): ~7.5 mm diameter—looks much larger . Implication for buyers : If you want a larger-looking stone for the same budget, emeralds, aquamarines, or opals provide more "visual carat" than diamonds. However, diamonds are harder (Mohs 10) and more durable for daily wear. Cut also matters : A shallow-cut diamond may "spread" to look larger but sacrifices brilliance. A deep-cut diamond looks smaller but may have better light performance. Conclusion : Carat weight alone doesn't determine visual size—gemstone density and cut proportions both matter.

7. Are lab-grown diamonds measured in carats?

Yes, lab-grown (synthetic) diamonds are measured in carats identically to natural diamonds. They are chemically, physically, and optically identical to natural diamonds—pure crystalline carbon (C) with the same hardness (Mohs 10), refractive index (2.42), and density (3.52 g/cm³). Gemological laboratories (GIA, IGI) grade lab-grown diamonds using the same Four Cs (carat, cut, color, clarity) and issue certificates specifying exact carat weight. Key differences : Origin : Lab-grown created in controlled environments (HPHT or CVD methods) in weeks; natural formed over billions of years deep in Earth's mantle. Price : Lab-grown cost 30-70% less than natural diamonds of equivalent quality (e.g., 1 ct lab-grown ~$1,500-$3,000; natural ~$5,000-$8,000). Disclosure : Sellers must disclose lab-grown status; GIA certificates clearly state "laboratory-grown." Market : Growing acceptance, especially among younger, budget-conscious, or environmentally-minded buyers. Some prefer natural for rarity/tradition; others prefer lab-grown for value/ethics. Carat weight identical : 1 carat lab-grown = 200 mg, same as natural.

8. How accurate are carat weight measurements?

Modern carat weight measurements are extremely accurate , thanks to precision electronic scales: Precision : Gemological laboratories use scales calibrated to ±0.001 carat (±0.2 mg), often better. For reference, that's ~1/5th the weight of a single grain of table salt. Calibration : Scales are regularly calibrated against traceable reference standards linked to the SI kilogram (maintained by the International Bureau of Weights and Measures). Environmental control : Measurements performed in temperature-controlled rooms (~20-25°C) to prevent thermal expansion affecting readings. Cleaning : Gemstones cleaned before weighing (dirt, oils, or dust add weight). Repeatability : Multiple measurements averaged to ensure consistency. Certification : GIA, IGI, AGS certificates report carat weight to 0.01 ct (1 point) for consistency: e.g., "1.27 carats," measured to ±0.005 ct. Legal enforcement : Selling gemstones with misrepresented carat weight is fraud in most jurisdictions, punishable by fines and criminal penalties. Result : Carat weight is the most objective, precise, and reproducible of the Four Cs—far more consistent than subjective cut, color, or clarity grading.

9. What does "points" mean in diamond terminology?

In gem trade, 1 carat = 100 points , so 1 point = 0.01 carat = 2 milligrams . "Points" terminology allows precise description of smaller gemstones and fractional carats: Common examples : "50-pointer" = 0.50 carat (50 points). "75-point diamond" = 0.75 carat. "10-point melee" = 0.10 carat (small accent stones). "One-pointer" = 0.01 carat (tiny chip diamonds used in pavé settings). Why use points? Easier for small stones : Saying "ten-pointer" is quicker than "zero-point-one-carat." Pricing precision : Allows price-per-point calculations for wholesale. Trade jargon : Professional jewelers, cutters, and traders use points routinely. Historical : Predates electronic scales; points allowed finer distinctions than early balance scales. Example in retail : "This ring features a 75-point center diamond surrounded by 20 points total weight of accent stones" = 0.75 ct + 0.20 ct = 0.95 ct total carat weight (TCW). Note : While points are common in trade, consumer-facing marketing usually uses decimals: "0.50 ct" rather than "50 points."

10. Why did ancient people use carob seeds to weigh gems?

Ancient Mediterranean merchants used carob seeds ( Ceratonia siliqua ) as counterweights on balance scales because they believed these seeds had remarkably uniform weight —approximately 200 milligrams each , close to today's carat standard. Practical advantages : Abundance : Carob trees grew widely across Mediterranean (Greece, Italy, Middle East), making seeds readily available. Portability : Small, lightweight seeds easy to carry in pouches for trade. Durability : Dried carob seeds don't decay quickly; can be stored for years. Size : Perfect for weighing small, valuable items (gems, gold, spices, medicines). Ancient trade : Greek, Roman, Arab, and Persian merchants traveled long distances with balance scales and carob seeds, facilitating gem trade across continents. The belief in uniformity : Ancient texts suggest carob seeds were thought to have nearly identical weights, making them natural standard units. Reality : Modern analysis shows carob seeds actually vary by 10-20% (180-220 mg), so ancient weights weren't as precise as believed. However, the average (~200 mg) happens to closely match the modern carat, suggesting ancient merchants intuitively converged on a practical standard that persists today.

11. Can you haggle over carat weight when buying diamonds?

No, carat weight is objectively measurable and non-negotiable —a 1.00 ct diamond weighs exactly 200 mg, confirmed by precision scales. You cannot "haggle" to get 1.10 ct weight for the price of 1.00 ct. What you CAN negotiate : Price per carat : Total cost for the specific diamond (negotiating discount on asking price). Quality trade-offs : Choosing lower color (G vs. D), lower clarity (VS2 vs. VVS1), or different cut to stay within budget while maximizing carat. Just-below milestones : Purchasing 0.90 ct instead of 1.00 ct saves 15-20% with negligible visual difference—smart buying strategy, not haggling on weight. Total jewelry piece : Negotiating on the setting, band material, or package deal (ring + earrings). Trade-in : Bringing old jewelry to trade toward purchase. Timing : Shopping during sales (Black Friday, Valentine's Day) or at end of month/quarter when sellers have targets. What sellers CANNOT do : Misrepresent carat weight. Gemological certificates from GIA/IGI specify exact weight. If a seller claims a 1.00 ct diamond weighs more/less than 200 mg, it's either fraud or an error. Pro tip : Focus negotiations on price-per-carat reduction or value-adds (free resizing, upgraded setting), not on changing the actual diamond weight.

12. How has the carat system changed with modern technology?

The carat definition (200 mg) remains unchanged since 1907 , but technology has revolutionized measurement, cutting, and trade : Precision scales : Modern electronic scales measure to ±0.001 ct (±0.2 mg) vs. early 20th-century balance scales (±0.05-0.10 ct). Ensures consistent global trade. Laser cutting : Computer-controlled lasers cut diamonds with micron-level precision, optimizing yield from rough and maximizing brilliance for a given carat weight. Can achieve ideal proportions consistently. 3D scanning : Machines scan rough diamonds in seconds, calculating optimal cut to maximize carat weight retention while achieving excellent proportions. Before: Cutters relied on experience; now: Algorithms optimize. Synthetic diamonds : Lab-grown diamonds (HPHT, CVD) can be produced to target carat weights, unlike mining where sizes are random. Enables consistent supply of specific sizes. Online retail : Internet sellers (Blue Nile, James Allen) list thousands of diamonds with exact carat weights, photos, 360° videos. Buyers filter by precise carat ranges (1.00-1.25 ct). Blockchain tracking : Some companies use blockchain to track diamonds from mine to retail, recording carat weight at each stage, enhancing transparency. AI grading : Emerging AI systems assist gemologists in assessing cut quality and predicting optimal finished carat weight from rough. Result : The carat unit is stable, but technology makes measurement, cutting, and trading far more precise, efficient, and transparent than ever before.

How many grams are in a Dina?

1 Dina is exactly equal to 0.00006479891 grams (g), which is the same as 64.79891 milligrams (mg).

Is Dina related to Grain?

Yes, the Dina is effectively identical to the Grain (gr) unit in terms of mass. 1 Dina = 1 Grain.

Is Dina commonly used today?

No, the term 'Dina' for this weight is extremely rare and primarily of historical or theoretical interest. The Grain unit itself sees niche use (e.g., ammunition), but not typically under the name 'Dina'.

How many drams are in an ounce (avoirdupois)?

Exactly 16 avoirdupois drams = 1 avoirdupois ounce. This is the definition: 1 oz av = 16 dr av 1 dr av = 1/16 oz av = 0.0625 oz

How many grams are in a dram (avoirdupois)?

1 avoirdupois dram = 1.7718451953125 grams (exactly). Practical approximation: 1 dr av ≈ 1.77 g Derivation: 1 pound av = 453.59237 grams (exact) 1 pound = 256 drams 1 dram = 453.59237 ÷ 256 = 1.77185 g

Is a dram a unit of mass or volume?

Both exist, which causes significant confusion: Mass (weight): Avoirdupois dram (dr): 1.772 g Apothecary dram (ʒ): 3.888 g Volume: Fluid dram (fl dr, US): 3.697 mL Fluid dram (fl dr, imperial): 3.552 mL Context matters: Pharmacy/medicine historically: could be either (check symbols) General commerce: usually weight Modern usage: rare except ammunition (weight-related rating)

What's the difference between avoirdupois and apothecary drams?

Avoirdupois dram (commercial): 1/16 ounce avoirdupois 27.34375 grains 1.772 grams Used for general goods Apothecary dram (pharmaceutical): 1/8 ounce apothecary 60 grains 3.888 grams Used for medicines Key difference: Apothecary dram is 2.19× heavier than avoirdupois dram.

What does the symbol ʒ mean?

The symbol ʒ represents the apothecary dram. Origin: Scribal abbreviation of Latin "drachma" or "dragma." Appearance: Resembles a fancy number "3," which is appropriate since 1 dram = 3 scruples. Usage: Historical pharmaceutical prescriptions: "℞ Morphine ʒi" = Take 1 dram of morphine

What is a dram equivalent in ammunition?

"Dram equivalent" is a velocity/power rating for shotgun shells, not actual powder weight. Historical context: Black powder shotgun loads used actual drams of powder (e.g., "3 drams of black powder"). Modern meaning: A "3 dram equivalent" smokeless powder load produces approximately the same muzzle velocity as a historical 3-dram black powder load. Actual powder weight: Modern "3 dram equivalent" loads typically contain 18-22 grains of smokeless powder (less than 1 actual dram by weight). Rating scale: 2¾ dram eq: Light/target 3 dram eq: Standard 3¼ dram eq: Magnum 3¾ - 4 dram eq: Heavy magnum

Do doctors still use drams?

No, modern medicine uses metric units exclusively. Historical use: 19th and early 20th century physicians wrote prescriptions using apothecary measurements including drams (ʒ). Transition: UK: Abandoned apothecary units in 1970 US: Phased out 1970s-1990s Current practice: All modern prescriptions use milligrams (mg), grams (g), and milliliters (mL). Drams are historical artifacts.

How do I convert historical dram measurements?

Step 1: Identify the system Pharmacy/medicine: Likely apothecary dram (3.888 g) Cooking/commerce: Likely avoirdupois dram (1.772 g) Step 2: Check for symbols ʒ symbol: Definitely apothecary "dr" or no symbol: Context-dependent (probably avoirdupois for cooking) Step 3: Convert to grams Avoirdupois: drams × 1.772 Apothecary: drams × 3.888 Step 4: Convert to modern measure Grams to teaspoons (dry ingredients): ~5 g per tsp Grams to milliliters (liquids): depends on density

Can I still buy dram weights?

Yes, as antique collectibles, but not for practical use. Antique apothecary weights: Available from antique dealers, often brass or bronze, marked with ʒ symbol. Modern equivalents: Not manufactured. Use gram scales instead. Collectible value: Complete sets of 18th-19th century apothecary weights command $100-500+ depending on condition.

Why did pharmacy abandon drams?

Multiple reasons drove metrication: 1. International standardization: Metric system adopted globally for science and medicine. 2. Safety: Multiple dram systems (avoirdupois vs. apothecary) created dangerous confusion. 3. Ease of calculation: Decimal metric system simpler than fractional apothecary system. 4. Precision: Milligrams allow more precise dosing than grains/scruples/drams. Result: By 1990, virtually all pharmacy worldwide used metric exclusively.

1. How many grains are in an ounce (avoirdupois)?

Exactly 437.5 grains. This is a defined relationship in the avoirdupois system: 1 pound (avoirdupois) = 7,000 grains 1 pound = 16 ounces 1 ounce = 7,000 ÷ 16 = 437.5 grains

2. How many grains are in a pound (avoirdupois)?

Exactly 7,000 grains. The avoirdupois pound is defined as 7,000 grains. This is the legal definition in both US and UK systems (since the 1959 international agreement). Example: A 1-pound bag of bullets contains 7,000 grains of lead.

3. How many milligrams are in a grain?

Exactly 64.79891 milligrams. This precise value comes from: 1 pound = 453.59237 grams (defined, 1959) 1 grain = 1/7000 pound 1 grain = 453.59237 ÷ 7000 = 0.06479891 g = 64.79891 mg

4. Why is ammunition measured in grains instead of grams?

Historical precedent and global standardization. Reasons: Ballistics data: Centuries of data in grains (velocity, energy, trajectory) Reloading manuals: All powder recipes in grains International standard: Even metric countries export ammo labeled in grains Precision: Grain scale (65 mg) well-suited for bullet weights (2-50 grams) Continuity: Changing would require recalibrating every firearm manual and table Result: The shooting industry worldwide uses grains, regardless of country.

5. Is a grain the same in troy, avoirdupois, and apothecaries' systems?

Yes, exactly the same. The grain is the only unit shared identically across all three systems: 1 grain (avoirdupois) = 64.79891 mg 1 grain (troy) = 64.79891 mg 1 grain (apothecaries') = 64.79891 mg Why this matters: The grain is the common denominator , allowing conversion between systems. Example: 480 grains = 1 troy ounce = 1 apothecaries' ounce 437.5 grains = 1 avoirdupois ounce (different!)

6. How many grains are in a gram?

Approximately 15.43236 grains. Formula: 1 gram = 1,000 mg 1 grain = 64.79891 mg 1 gram = 1,000 ÷ 64.79891 = 15.43236 grains Quick approximation: 1 gram ≈ 15.4 grains (useful for mental math)

7. What does "5 grain aspirin" mean?

A tablet containing 5 grains of aspirin = 325 milligrams. Calculation: 5 grains × 64.79891 mg/grain = 323.99 mg ≈ 325 mg Why 325 mg tablets? Historical: Aspirin was formulated in grain dosages. When pharmacy metricated, 5 grains became 325 mg (rounded for convenience).

8. How much does a barleycorn actually weigh?

About 50-70 milligrams, depending on variety. Modern grain vs. actual barleycorn: Defined grain: 64.79891 mg (EXACT) Actual barleycorn: 50-70 mg (varies) Remarkably close! Medieval barleycorns averaged ~65 mg, very close to the modern definition. Why the difference today? The grain is now a defined constant , not dependent on actual barley. This ensures global consistency.

9. Why is the grain 1/7000 of a pound?

Historical evolution, not mathematical planning. Theory: The pound and grain evolved separately: Grain: Ancient seed weight Pound: Medieval trade weight The 7,000-grain pound emerged from trade practices and was standardized by law (13th-14th century England). Convenience: 7,000 is highly divisible (1, 2, 4, 5, 7, 8, 10, 14, 20, 25, 28, 35, 40, 50, 56, 70, 100, 125, 140, 175, 200, 250, 280, 350, 500, 700, 1000, 1400, 1750, 2333, 3500, 7000), making fractional calculations easier in pre-calculator commerce.

10. Do other countries use grains?

Yes, for ammunition and archery worldwide. By country: United States: Grains for ammo, archery, some pharmaceuticals United Kingdom: Grains for ammo, archery (pharmacy now metric) Europe: Grains for ammunition exports, some domestic ammo Asia, Australia: Grains for ammunition, archery Pharmaceutical use: Mostly obsolete outside the U.S. (switched to milligrams). Why grains persist globally: Ammunition is an international market. Standardization on grains ensures compatibility.

11. How accurate do reloading scales need to be?

±0.1 grain (±0.0065 grams) minimum. Why such precision? Small powder charges: 3-10 grains (pistol), 20-60 grains (rifle) ±0.1 grain = ±1-3% variation (acceptable) ±1 grain = ±10-30% variation (dangerous!) Scale types: Beam balance: Manual, ±0.1 grain typical Digital: Electronic, ±0.1 grain or better Trickler: Adds powder grain-by-grain for exactness Safety: Reloading is unforgiving. Precision scales are essential to avoid overpressure, case ruptures, or injuries.

12. What is the relationship between grain and carat?

1 carat (gemstone) = 200 milligrams = 3.086 grains. Calculation: 1 carat = 200 mg 1 grain = 64.79891 mg 1 carat = 200 ÷ 64.79891 = 3.086 grains Historical connection: Both derive from seeds: Grain: Barleycorn Carat: Carob seed (~200 mg) Modern difference: Carat: Used for gemstones (diamonds, rubies, sapphires) Grain: Used for bullets, arrows, pharmaceuticals Overlap: Small gemstones or pearls historically measured in grains; now almost exclusively carats.

How many grams are in a Kati?

A Kati, when considered equivalent to the standard Tola, is equal to exactly 11.6638038 grams (based on the Tola being 180 grains). It is often rounded to 11.664 grams for practical purposes. Note that minor historical or regional variations might exist.

Is Kati related to the Chinese Catty?

No, despite the similar name, the Indian Kati (~11.66 grams) is entirely distinct from the Catty (also sometimes spelled Kati) used in East and Southeast Asia. The Chinese Catty is a much larger unit, typically around 600 grams (though its value also varies by region, e.g., ~604.8g in Malaysia/Singapore). They are unrelated units from different traditional systems.

Is Kati commonly used today?

The Kati is not commonly used in everyday trade or official measurements in India today, having been largely replaced by the gram and kilogram. However, the term might still be recognized or occasionally used in very specific traditional contexts, such as by older generations, in rural markets, or within the traditional jewelry trade, often interchangeably with 'Tola'.

How much is 1 kilogram visually?

One kilogram is about the weight of a liter bottle of water or a small laptop . Visual comparisons : 1 liter of water : Exactly 1 kg (at 4°C) Bag of sugar : Typically 1 kg or 2 kg Small laptop : 1-1.5 kg Two pineapples : About 1 kg total Medium-sized book : Approximately 1 kg Loaf of bread : About 0.5-0.8 kg (1 kg for larger loaves) Body reference : For most people, 1 kg is slightly heavier than can be easily held in one hand for extended periods About 2-3% of average adult body weight To remember : Picture a standard milk or water bottle (1 liter) - that's 1 kilogram.

Weight Unit Converter

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About Weight Conversions

Convert between different units of weight or mass

Convert between 24 different weight units including Kilogram, Gram, Milligram, Pound, Ounce, and more. Our free online converter provides instant, accurate conversions with formulas, examples, and conversion tables.

Quick Start: Weight Conversions

Convert between 25+ weight and mass units instantly. Perfect for cooking, fitness tracking, shipping calculations, and international travel.

Most Popular Conversions:

Kilograms to Pounds - Fitness & body weight
Pounds to Kilograms - International standards
Grams to Ounces - Cooking & recipes
Ounces to Grams - Baking precision
Stone to Pounds - UK body weight

Understanding Weight and Mass Conversions

Weight and mass are fundamental measurements used daily, from cooking recipes to calculating shipping costs. While technically distinct (mass is the amount of matter, weight is the force of gravity on that mass), the terms are often used interchangeably in everyday contexts.

Why Weight Conversion Matters

Cooking & Baking: Recipe ingredients may be listed in grams (metric) or ounces/pounds (imperial). Precision matters—especially in baking where ratios affect chemical reactions.

Fitness & Health: Body weight tracking requires conversions when traveling internationally. Gym weights use pounds in the US but kilograms elsewhere.

Shipping & Logistics: International shipping requires weight in kilograms, while domestic US shipping uses pounds. Incorrect conversions affect costs and compliance.

Science & Medicine: Laboratory measurements use metric exclusively (milligrams, micrograms). Medical dosing requires extreme precision to avoid dangerous errors.

Precious Metals & Gems: Gold, silver, and diamonds use specialized units (troy ounces, carats) requiring accurate conversions for trading.

Common Weight/Mass Units Explained

Metric System (International)

Kilogram (kg) - Base Unit: The fundamental unit of mass in the SI system. Originally defined by a physical platinum-iridium cylinder in Paris, now defined by fundamental constants. Used worldwide for body weight, food, and commerce.

Gram (g): 1/1,000th of a kilogram (0.001 kg). Perfect for cooking ingredients, small items, and postal weights. A standard paperclip weighs about 1 gram.

Milligram (mg): 1/1,000th of a gram (0.001 g). Critical for medication dosing, nutritional supplements, and laboratory measurements.

Microgram (μg): 1/1,000,000th of a gram (10⁻⁶ g). Used for vitamin measurements, pharmaceutical formulations, and environmental standards.

Metric Ton (tonne, t): 1,000 kilograms (2,204.62 lbs). Used for large quantities—vehicles, cargo, industrial materials, agricultural yields.

Imperial / US Customary System

Pound (lb): The primary weight unit in the US, equal to 16 ounces or approximately 453.592 grams. Used for body weight, groceries, and package shipping in the US.

Ounce (oz): 1/16th of a pound (about 28.35 grams). Common for food portions, postal mail, and small package weights. Note: different from fluid ounces (volume).

Stone (st): 14 pounds (6.35 kg). Traditional unit for body weight in the UK and Ireland. "I weigh 11 stone" = 154 pounds = 70 kg.

US Ton (short ton): 2,000 pounds (907.185 kg). Used in the US for large weights—trucks, construction materials, coal.

Specialized Units

Troy Ounce (oz t): 31.1035 grams (heavier than regular ounce). Standard for precious metals—gold, silver, platinum. Gold prices are quoted per troy ounce.

Carat (ct): 200 milligrams (0.2 g). Used exclusively for gemstones and pearls. A 1-carat diamond weighs 0.2 grams.

Grain (gr): 64.79891 milligrams. Historically important, still used for bullets, arrows, and pharmaceutical measurements.

Conversion Quick Reference

Metric ↔ Imperial Conversions

From	To	Multiply By	Example
Kilograms	Pounds	2.20462	5 kg = 11.02 lbs
Pounds	Kilograms	0.453592	10 lbs = 4.54 kg
Grams	Ounces	0.035274	100 g = 3.53 oz
Ounces	Grams	28.3495	5 oz = 141.75 g
Stone	Kilograms	6.35029	10 st = 63.5 kg
Kilograms	Stone	0.157473	70 kg = 11.02 st

Within Metric System

From	To	Multiply By
Kilograms	Grams	1,000
Grams	Milligrams	1,000
Milligrams	Micrograms	1,000
Metric Tons	Kilograms	1,000

Within Imperial System

From	To	Multiply By
Pounds	Ounces	16
Stone	Pounds	14
US Tons	Pounds	2,000
Troy Ounces	Regular Ounces	1.09714

Practical Conversion Examples

Cooking & Baking

Common Ingredients:

Flour: 1 cup = 120-130g = 4.2-4.6 oz
Sugar (granulated): 1 cup = 200g = 7 oz
Butter: 1 stick = 113g = 4 oz = 1/2 cup
Eggs: 1 large egg = 50g = 1.76 oz

Recipe Scaling:

European recipe calls for 250g flour = 8.8 oz (about 2 cups)
US recipe calls for 8 oz cream cheese = 227g
Baking powder: 5g = 1 teaspoon (critical for precision)

Fitness & Body Weight

Weight Tracking:

150 lbs = 68.04 kg (common adult weight)
200 lbs = 90.72 kg
70 kg = 154.32 lbs = 11 stone
Weight loss: 10 lbs = 4.54 kg

Gym Weights:

45-lb barbell plate = 20.4 kg (standard Olympic bar)
25-lb dumbbell = 11.3 kg
Bench press 185 lbs = 84 kg

Shipping & Postal

Package Weights:

USPS First Class limit: 15.99 oz = 453g (just under 1 lb)
Priority Mail envelope: up to 70 lbs = 31.75 kg
International air cargo: priced per kg
Overweight baggage fee: >50 lbs (22.68 kg)

Bulk Shipping:

Pallet weight: 1,500 lbs = 680 kg
Container load: 20 tons = 18,144 kg (metric tons)

Medical & Pharmaceutical

Medication Dosing:

Aspirin tablet: 325 mg = 0.325 g
Acetaminophen: 500 mg dose
Vitamin D: 1,000 IU = 25 μg (micrograms)
Birth control: 30 μg dosage (⚠️ Never confuse μg with mg!)

Body Measurements:

Birth weight: 7 lbs 8 oz = 3.4 kg
Newborn average: 3.5 kg = 7.7 lbs
Adult blood volume: ~5 liters ≈ 5 kg ≈ 11 lbs

Common Conversion Mistakes to Avoid

Mistake 1: Confusing Weight with Volume

Error: "1 pound of flour = 1 cup" Correction: Weight and volume are different. 1 pound flour ≈ 3.5-4 cups (density matters). Always convert weight to weight, volume to volume.

Mistake 2: Wrong Ounce Type

Error: Using fluid ounces (fl oz) for weight conversions Correction: Fluid ounces measure volume; regular ounces (oz) measure weight. They're only equal for pure water (1 fl oz water ≈ 1 oz weight).

Mistake 3: Incorrect Kg-to-Lbs Factor

Error: "1 kg = 2 lbs" Correction: 1 kg = 2.20462 lbs (not 2.0). Using 2.0 causes 10% error. For quick estimates, 2.2 is better.

Mistake 4: Metric Ton vs US Ton

Error: "1 ton = 1,000 kg" (when working in US context) Correction: Specify which ton! Metric ton (tonne) = 1,000 kg. US ton = 2,000 lbs ≈ 907 kg. UK long ton = 2,240 lbs ≈ 1,016 kg.

Mistake 5: Stone Conversion Errors

Error: "10 stone = 100 lbs" Correction: 10 stone = 140 lbs (14 lbs per stone), not 100 lbs. Stone is only used in UK/Ireland.

Mistake 6: Microgram-Milligram Confusion

Error: Taking 1 mg when prescribed 1 μg Correction: 1 mg = 1,000 μg. This is a 1,000x overdose! Always double-check μg vs mg on labels.

Frequently Asked Questions

How many pounds are in a kilogram?

There are approximately 2.20462 pounds in 1 kilogram.

Formula: pounds = kilograms × 2.20462

Examples:

1 kg = 2.20462 lbs (about 2 lbs 3 oz)
5 kg = 11.02 lbs
10 kg = 22.05 lbs
70 kg (adult weight) = 154.32 lbs

Quick mental math: Multiply kg by 2.2 for a close estimate.

Convert Kilograms to Pounds →

How do I convert pounds to kilograms?

To convert pounds to kilograms, multiply by 0.453592 (or divide by 2.20462).

Formula: kilograms = pounds × 0.453592

Examples:

1 lb = 0.454 kg
10 lbs = 4.54 kg
150 lbs (adult weight) = 68.04 kg
200 lbs = 90.72 kg

Quick mental math: Divide pounds by 2.2 for an estimate.

Convert Pounds to Kilograms →

How many grams are in an ounce?

There are approximately 28.3495 grams in 1 ounce (avoirdupois ounce).

Formula: grams = ounces × 28.3495

Examples:

1 oz = 28.35 g
4 oz (quarter pound) = 113.4 g
8 oz (half pound) = 226.8 g
16 oz (1 pound) = 453.6 g

Note: Troy ounces (for precious metals) = 31.1035 grams (heavier).

Convert Ounces to Grams →

What is the difference between an ounce and a fluid ounce?

Ounce (oz): Measures weight/mass

1 oz ≈ 28.35 grams
Example: "4 oz of chicken breast"

Fluid Ounce (fl oz): Measures volume (liquid capacity)

1 fl oz ≈ 29.57 milliliters
Example: "8 fl oz of milk"

Key point: They're NOT directly convertible without knowing density. 1 fl oz of water weighs about 1 oz, but 1 fl oz of honey weighs more (denser), and 1 fl oz of air weighs almost nothing.

How many pounds are in a stone?

There are exactly 14 pounds in 1 stone.

Formula: pounds = stone × 14

Examples:

1 stone = 14 lbs (6.35 kg)
10 stone = 140 lbs (63.5 kg)
11 stone = 154 lbs (70 kg) - common adult weight
15 stone = 210 lbs (95.25 kg)

Usage: Stone is used for body weight in the UK and Ireland but rarely elsewhere.

Convert Stone to Pounds →

How many ounces are in a pound?

There are exactly 16 ounces in 1 pound.

Formula: ounces = pounds × 16

Examples:

1 pound = 16 oz
0.5 pounds (half pound) = 8 oz
2 pounds = 32 oz
5 pounds = 80 oz

Quick fractions:

Quarter pound = 4 oz
Half pound = 8 oz
Three-quarter pound = 12 oz

Convert Pounds to Ounces →

What's the easiest way to estimate kilograms to pounds?

Quick estimate: Multiply kilograms by 2.2 to get pounds.

Mental math tricks:

Double and add 10%: For 5 kg: 5 × 2 = 10, plus 10% = 11 lbs (actual: 11.02)
Use 2.2 multiplier: 10 kg × 2.2 = 22 lbs (precise: 22.05)

Common weights memorized:

1 kg ≈ 2.2 lbs
5 kg ≈ 11 lbs
10 kg ≈ 22 lbs
50 kg ≈ 110 lbs
100 kg ≈ 220 lbs

Convert Kilograms to Pounds →

What is the difference between a metric ton and a US ton?

Metric Ton (tonne, t):

1,000 kilograms
2,204.62 pounds
Used internationally

US Ton (short ton):

2,000 pounds
907.185 kilograms
Used in United States

UK Long Ton:

2,240 pounds
1,016.047 kilograms
Rarely used today

Comparison: A metric ton is about 10% heavier than a US ton.

Which to use:

International shipping/trade: metric tons
US domestic: US tons
Always specify which type!

How do I quickly convert grams to pounds?

Method 1 - Direct: Divide grams by 453.6

500 g ÷ 453.6 ≈ 1.1 lbs

Method 2 - Via kg: Convert to kg first, then to lbs

500 g = 0.5 kg × 2.2 = 1.1 lbs

Formula: pounds = grams × 0.00220462

Examples:

100 g = 0.22 lbs (about 3.5 oz)
250 g = 0.55 lbs (about half pound)
500 g = 1.10 lbs
1,000 g (1 kg) = 2.20 lbs

Convert Grams to Pounds →

What unit of weight is typically used for groceries?

United States:

Produce: pounds and ounces
Meat: pounds (e.g., "1.5 lbs ground beef")
Deli items: pounds and ounces
Packaged goods: ounces or pounds

Metric Countries (Europe, Asia, most of world):

Produce: kilograms and grams
Meat: kilograms (e.g., "500g chicken")
Deli items: grams
Packaged goods: grams or kilograms

Dual labeling: Many products show both systems (e.g., "Net Wt 16 oz (454g)").

How many milligrams are in a gram?

There are exactly 1,000 milligrams in 1 gram.

Formula: milligrams = grams × 1,000

Metric prefix meanings:

"Milli-" means one-thousandth (1/1,000)
So 1 gram = 1,000 milligrams
And 1 milligram = 0.001 grams

Examples:

Aspirin tablet: 325 mg = 0.325 g
Vitamin C: 1,000 mg = 1 g
Tylenol: 500 mg = 0.5 g
Antibiotic dose: 250 mg = 0.25 g

Is a kilogram heavier than a pound?

Yes, a kilogram is significantly heavier than a pound. Specifically:

1 kilogram ≈ 2.2 pounds (more than double)
1 pound ≈ 0.45 kilograms (less than half)

Visual comparison:

Bag of sugar (US): 5 lbs = 2.27 kg
Bag of sugar (metric): 2 kg = 4.4 lbs

Practical example: If you weigh 150 lbs, that's 68 kg (about 45% of the pounds value).

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Complete alphabetical list of all weight conversion pairs. Each conversion page includes formulas, examples, and conversion tables.

Frequently Asked Questions about Weight/

Answer: 1 u = 1.660 539 066 60 × 10⁻²⁷ kg (with standard uncertainty ±0.000 000 000 50 × 10⁻²⁷ kg) This extraordinarily precise value comes from measurements of carbon-12 atoms using mass spectrometry and relates to the newly defined kilogram (based on Planck's constant as of 2019). Approximate value: 1 u ≈ 1.6605 × 10⁻²⁷ kg In grams: 1 u ≈ 1.6605 × 10⁻²⁴ g Memorization tip: "1.66 and exponent −27" Uncertainty: The precision is about 0.3 parts per billion (extremely accurate!) Source: CODATA 2018 recommended values (Committee on Data for Science and Technology)

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Learn more about unit conversion with our comprehensive guides. Master weight conversions and explore other measurement systems:

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Weight Unit Converter

About Weight Conversions

Quick Start: Weight Conversions

Understanding Weight and Mass Conversions

Why Weight Conversion Matters

Common Weight/Mass Units Explained

Metric System (International)

Imperial / US Customary System

Specialized Units

Conversion Quick Reference

Metric ↔ Imperial Conversions

Within Metric System

Within Imperial System

Practical Conversion Examples

Cooking & Baking

Fitness & Body Weight

Shipping & Postal

Medical & Pharmaceutical

Common Conversion Mistakes to Avoid

Mistake 1: Confusing Weight with Volume

Mistake 2: Wrong Ounce Type

Mistake 3: Incorrect Kg-to-Lbs Factor

Mistake 4: Metric Ton vs US Ton

Mistake 5: Stone Conversion Errors

Mistake 6: Microgram-Milligram Confusion

Frequently Asked Questions

How many pounds are in a kilogram?

How do I convert pounds to kilograms?

How many grams are in an ounce?

What is the difference between an ounce and a fluid ounce?

How many pounds are in a stone?

How many ounces are in a pound?

What's the easiest way to estimate kilograms to pounds?

What is the difference between a metric ton and a US ton?

How do I quickly convert grams to pounds?

What unit of weight is typically used for groceries?

How many milligrams are in a gram?

Is a kilogram heavier than a pound?

Related Converters

Popular Weight Conversion Pairs

Popular Weight Conversion Pairs

Complete List: All Weight Unit Conversions

Frequently Asked Questions about Weight/

What is the value of 1 u (or Da) in kilograms?

Is the atomic mass unit (amu) the same as the Dalton (Da)?

Why was Carbon-12 chosen as the standard for atomic mass?

How does the atomic mass unit relate to Avogadro's number?

What is the difference between atomic mass and atomic weight?

Can I use atomic mass units for objects larger than molecules?

How accurate are modern atomic mass measurements?

Do protons and neutrons have exactly the same mass?

Why is the atomic mass of hydrogen 1.008 u instead of 1 u?

Will the definition of the atomic mass unit ever change?

1. How many milligrams are in a carat?

2. How many grams are in a carat?

3. Is carat the same as karat?

4. Why do diamonds cost more per carat as size increases?

5. What's the largest diamond ever found?

6. Do all gemstones of the same carat weight look the same size?

7. Are lab-grown diamonds measured in carats?

8. How accurate are carat weight measurements?

9. What does "points" mean in diamond terminology?

10. Why did ancient people use carob seeds to weigh gems?

11. Can you haggle over carat weight when buying diamonds?

12. How has the carat system changed with modern technology?

How many grams are in a Dina?

Is Dina related to Grain?

Is Dina commonly used today?

How many drams are in an ounce (avoirdupois)?

How many grams are in a dram (avoirdupois)?

Is a dram a unit of mass or volume?

What's the difference between avoirdupois and apothecary drams?

What does the symbol ʒ mean?

What is a dram equivalent in ammunition?

Do doctors still use drams?

How do I convert historical dram measurements?

Can I still buy dram weights?

Why did pharmacy abandon drams?

1. How many grains are in an ounce (avoirdupois)?

2. How many grains are in a pound (avoirdupois)?