Which gem is the hardest natural mineral?
AnswerDiamond
Diamond scores 10 on the Mohs hardness scale.
Fashion · Facts & stats
Bling facts & stats
7 fact-checked facts about jewelry, gemstones and sparkle, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
Which gem forms inside oysters and other mollusks?
AnswerPearl
Pearls grow in layers of nacre around an irritant.
Going deeper
How many karats is pure gold?
Answer24
24-karat gold is essentially pure gold.
Rubies and sapphires are both forms of which mineral?
AnswerCorundum
Red corundum is ruby; other colors are sapphire.
What are the '4 Cs' of diamond grading?
AnswerCut, color, clarity and carat
The 4 Cs system was popularized by the GIA.
Expert level
Which famous blue diamond is displayed at the Smithsonian?
AnswerThe Hope Diamond
The Hope Diamond was donated in 1958.
One carat, the unit for weighing gems, equals how much?
Answer200 milligrams
Five carats make one gram.
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