Overview
The carat (ct) is a standardized unit of mass for gemstones and pearls, universally adopted in the jewelry trade. One carat equals 200 milligrams or 0.2 grams. Its name derives from the carob seeds historically used as counterweights in balance scales due to their uniform size. The modern carat was standardized in 1907 by the Fourth General Conference on Weights and Measures to ensure consistency in gemstone trading. Unlike the 'karat' (a measure of gold purity), the carat exclusively quantifies weight, not quality or composition.
Key Features
Carat weight is a primary determinant of a gemstone's value, alongside cut, color, and clarity. Precision is critical: even a 0.01-ct difference can significantly impact pricing, especially for diamonds. Jewelers use microbalances calibrated to 0.001 ct for accuracy. The carat is subdivided into 100 'points,' allowing precise descriptions (e.g., 0.75 ct = 75 points). Larger stones are rarer and thus exponentially more valuable per carat. For example, a 2-ct diamond typically costs far more than two 1-ct diamonds of similar quality.
Application Areas
Carat measurement is essential in gemstone mining, cutting, trading, and retail. Miners assess rough stone weight to estimate potential yield, while cutters optimize carat retention during shaping. Traders use carat-based pricing models, and retailers highlight carat weight in consumer marketing. Beyond diamonds, carats apply to colored gemstones like rubies, sapphires, and emeralds. Pearls may be measured in carats or grains (1 grain = 0.25 ct). Some markets, such as industrial diamonds, use carats for abrasive quality control.
Precautions
Miscommunication between 'carat' and 'karat' (gold purity) can lead to costly errors in transactions. Always verify the context—'ct' denotes carat (weight), while 'kt' or 'K' indicates karat (gold). Ensure weighing instruments are ISO-certified and regularly calibrated. Temperature and humidity fluctuations can affect measurements. For high-value stones, third-party certification (e.g., GIA, AGS) is recommended to confirm carat weight and other attributes.
B2B Procurement Guide
When sourcing gemstones by carat weight, prioritize suppliers with transparent grading reports from reputable labs. Bulk buyers should negotiate tiered pricing based on carat ranges (e.g., 0.90–0.99 ct vs. 1.00+ ct). Consider regional preferences: some markets favor 'magic sizes' (e.g., 0.50 ct, 1.00 ct) and pay premiums for them. For colored stones, note that density varies—a 1-ct ruby will be smaller than a 1-ct emerald due to differing specific gravities.
Related Manufacturers
- 主营：双壁波纹管、钢带管、缠绕结构壁B型管、克拉管、HDPE克拉管、大口径克拉管、DN300克拉管、HDPE缠绕结构壁管、HDPE双壁波纹管、大口径双壁波纹管、hdpe双壁波纹管、排水双壁波纹管、PE污水管、排污双壁波纹管、大口径PE钢带管、hdpe钢带管、HDPE钢带波纹管、钢带增强缠绕管、钢带波纹管、pe钢带波纹管、大口径钢带管、排污钢带波纹管
- 主营：夹竹桃、异奥卡、香附酮、儿茶素、白鲜碱、管花苷、紫檀芪、木栓醇、豆甾醇、植酸锌、苏木素、泽泻醇、龙血素、黄柏酮、蚱蜢酮、防己碱、葫芦素、乌甲素、印楝素、厚朴酚、皂苷元、标准品、双黄酮、樱桃苷、芝麻素
- 主营：pe排水管、地热管、ppr管、克拉管、钢丝网骨架管、pe管、pe给水管、hdpe双壁波纹管、波纹管、pe钢丝网骨架管
- 主营：X荧光检测仪、合金检测仪、贵金属检测仪、克拉级别鉴定仪器、镀层分析仪、矿石元素分析仪、环保检测、手持式合金检测、RoHS检测仪
- 主营：pe给水管、钢丝网骨架管、双壁波纹管、克拉管、钢带增强波纹管、mpp电力管、七孔梅花管、塑料检查井、钢带管、pe管、pe穿线管、pe排水管、cpvc电力管、pvc格栅管、玻璃钢夹砂管、井筒管、pvc双壁波纹管、HDPE双壁波纹管、排污管、农田灌溉管、拖拉管、顶管、钢带增强螺旋波纹管、梅花管、聚乙烯管
- 主营：克拉管、HDPE给水管、市政管道
- 主营：cpvc电力管、双壁排污波纹管、PE管、克拉管、pvc给水管、钢带波纹管、PE给水管、给水管、双壁波纹管、排水管、MPP电力管、钢丝网骨架管、钢带管、电缆护套管、电缆保护管、电力电缆保护管、电力保护管、缠绕结构壁B型管、波纹管、pe穿线管、热浸塑钢管、PVC-M给水管、PVC-O管材、格栅管、cpvc预埋电力管
- 主营：电力管、给水管、排水管、克拉管、波纹管、钢带管、灌溉管、双壁波纹管、pvc排水管、cpvc电力电缆管、PE灌溉管、钢带波纹管、MPP电力电缆管、碳素波纹管、梅花管、电力电缆管、钢塑缠绕管、箱包装饰骨条、置换抢修管、钢丝网骨架管、九孔格栅管、农田灌溉输水管、钢丝网骨架复合管、PVC双壁波纹管、农田灌溉管
- 主营：mpp电力管、排水管、给水管、克拉管、PE管、PVC管、pe给水管、pe排水管、PVC给水管、PVC排水管、pe穿线管
- 主营：pe给水管、HDPE波纹管、pvc农田灌溉、PE克拉管、大口径排水管
- 主营：四氟垫片、金属缠绕垫、氟橡胶垫片、膨体四氟垫片、四氟包覆垫片、三元乙丙橡胶垫片、石墨复合垫、丁青橡胶垫片、氯丁橡胶垫片、硅橡胶垫片、陶瓷纤维垫片、石棉橡胶垫、无石棉垫、石墨填料环、四氟生料带、金属包覆垫片
- 主营：灌浆料、高延性混凝土、风电灌浆料、环氧树脂灌浆料、路面快速修补料、环氧树脂砂浆、环氧树脂胶泥、孔道压浆料、UHPC超高性能混凝土、CPC防碳化涂料
- 主营：pe给水管、hdpe双壁波纹管、pe钢丝网骨架聚乙烯塑料复合管、克拉管、球墨铸铁井盖
- 主营：双金属堆焊耐磨衬板、20mn23alv钢板、耐候钢板耐酸钢板
- 主营：mpp电力管、pe给水管、PE盘管、克拉管生产厂商、PE管、HDPE给水管、mpp电力电缆保护管、给水管、钢带管、玻璃钢管、管道修复管、电缆保护管、电力波纹管、农田灌溉管、钢带波纹管、置换管、双壁波纹管、电力管、聚乙烯给水管、七孔梅花管、穿线管、硅芯管、钢丝网骨架塑料复合管、电缆保护套管、mpp电缆保护管、电力波纹护套管