Carat

Brooch with over 19 carats of cut diamonds
MFA# 2013.1776

Amethyst ring with 18kt gold
MFA# 2006.47

Description

1) A unit of weight for gemstones. One carat is 200 milligrams. Carat was used in the middle ages by alchemists.

2) (usually spelled karat) A unit of measure for the purity of gold. Pure gold is 24 karat or 1000 fine. A gold alloy that contains 75% gold is 18 karat or 750 fine.

Synonyms and Related Terms

karat; Karat (Deut.); carat (Fr.); fine

Resources and Citations

• David C. Scott, Metallography and Microstructure of Ancient and Historic Metals, The Getty Conservation Institute, Los Angeles, 1991

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997