O Carat Sistema: Measuring Gemstones
Understanding Diamond e Gemstone Peso
Experimente Peso ConversorQuando shopping for diamonds ou outro gemstones, carat weight é one of o primeiro things you'll encounter. But o que exatamente é a carat, e por que do gemstones use este unusual unidade instead of grams ou ounces? Este guia explains o carat sistema, its história, e como it affects gemstone value.
História of o Carat
O word "carat" comes from o carob seed (Ceratonia siliqua). In ancient times, gem traders usado carob seeds as counterweights on balance scales because o seeds foram believed to têm remarkably uniform weight.
In reality, carob seeds vary as much as 25% in weight—not muito uniform at todos! But o name stuck, e eventually o carat foi standardized.
Modern Standardization
In 1907, o Fourth General Conference on Weights e Measures definido o métrico carat as exatamente 200 milligrams (0.2 grams). Este padrão é agora usado worldwide, ending centuries of regional variation in carat definitions.
Carat Tabela de Conversão
| Carats | Milligrams | Grams | Ounces |
|---|---|---|---|
| 0.25 ct | 50 mg | 0.05 g | 0.0018 oz |
| 0.50 ct | 100 mg | 0.10 g | 0.0035 oz |
| 1.00 ct | 200 mg | 0.20 g | 0.0071 oz |
| 2.00 ct | 400 mg | 0.40 g | 0.0141 oz |
| 5.00 ct | 1000 mg | 1.00 g | 0.0353 oz |
Carat vs Karat: O que's o Difference?
Estes similar-sounding words measure completely diferente things:
| Term | Measures | Usado For |
|---|---|---|
| Carat (ct) | Peso | Diamonds, gemstones, pearls |
| Karat (K ou kt) | Purity | Gold alloy composition |
Exemplo: A 1-carat diamond in an 18-karat gold ring means a 200mg diamond in gold esse é 75% pure (18/24 = 75%).
Como Carat Peso Affects Valor
Diamond prices don't increase linearly com carat weight—they jump at "magic numbers":
Price Per Carat Increases
A 2-carat diamond isn't apenas twice o price of a 1-carat diamond; it's often 3-4 times o price. Larger diamonds são rarer, so price per carat increases as size increases.
Magic Numbers
Prices jump significantly at popular sizes:
- 0.50 carat (half carat)
- 0.75 carat (three-quarter)
- 1.00 carat (one carat)
- 1.50 carats
- 2.00 carats
A 0.99 carat diamond may cost significantly menos than a 1.00 carat diamond of identical quality because crossing o "one carat" threshold é psychologically important to buyers.
Carat Peso vs Size
Two diamonds of identical carat weight can appear diferente sizes due to their cut proportions. A shallow-cut diamond spreads its weight across a larger face-up area, appearing bigger. A deep-cut diamond concentrates weight in o bottom, appearing smaller but potentially sparkling mais.
Approximate Diamond Diameters (Round Brilliant)
| Carat Peso | Approximate Diameter |
|---|---|
| 0.25 ct | 4.1 mm |
| 0.50 ct | 5.2 mm |
| 0.75 ct | 5.9 mm |
| 1.00 ct | 6.5 mm |
| 1.50 ct | 7.4 mm |
| 2.00 ct | 8.2 mm |
Total Carat Peso (TCW)
Quando multiple gemstones são set together, jewelers report o "total carat weight" (TCW) ou "carat total weight" (CTW). A ring com one 0.50 ct center diamond e ten 0.05 ct accent diamonds tem a TCW of 1.00 ct.
Be careful: a 1.00 TCW ring com muitos small stones é worth far menos than a single 1.00 ct diamond, mesmo though o total weight é identical. Large diamonds são much rarer than small ones.
Conclusão
O carat, at exatamente 200 milligrams, é o universal padrão for medindo gemstone weight. While its name comes from ancient carob seeds, hoje's carat é precisamente definido e recognized worldwide.
Quando shopping for diamonds ou gemstones, remember esse carat weight é apenas one factor—cut, color, e clarity (o outro three "Cs") também significantly affect value e appearance.