What is the meaning of the karat mark on gold jewelry?
The fineness of jewelry gold is stated as the number of parts in twenty-four that are gold. Thus, 24 karat gold is pure gold; 12 karat would be an alloy that is half gold and half copper or other metals. And now you know. Join us again every weekday for a new CoreFact. For other CoreFacts, or for CoreCast, our in-depth science podcast, go to usgs.gov/podcasts. We are happily accepting your science questions, so if you’re curious about something that we can answer, send us an email at corefacts@usgs.gov or leave a voicemail at 703-648-5600, long distance fees apply. The USGS CoreFacts is a product of the U.S. Geological Survey, Department of the Interior.
