Gemology & Jewelry Lab

Gem & Jewelry Laboratory

Standardized carat measurements, karat alloy gold purity calculations, Troy ounce precious metal valuations, and historic UK assay hallmark decoding.

1. Input Weight & Unit

Gemology Metric Standard

The modern metric carat is exactly defined as 200 milligrams. Gem weights are traditionally quoted to two decimal places (points), where 1 point equals 0.01 carats.

2. Calculated Conversions

Metric Carats
1.00 ct
Grams (g)
0.200 g
Points (pt)
100.0 pt
Milligrams (mg)
200.0 mg
Gems Grains (gr) [Jeweler Trade Unit]
3.086 grains

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