Which gemstone is made of pure carbon?
AnswerDiamond
Diamond is crystallized carbon; rubies and sapphires are corundum.
Science · Facts & stats
Mining facts & stats
7 fact-checked facts about mining, minerals, ores and the history of mining, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
The 1849 gold rush took place mainly in which U.S. state?
AnswerCalifornia
Gold found at Sutter's Mill in 1848 set off the California Gold Rush of 1849.
Going deeper
Which mineral is a major ore of iron?
AnswerHematite
Hematite, an iron oxide, is one of the most important iron ores.
Galena is the main ore of which metal?
AnswerLead
Galena is lead sulfide, the primary source of lead.
The Klondike Gold Rush took place in which country?
AnswerCanada
The Klondike is in Canada's Yukon Territory; the rush peaked in the late 1890s.
Expert level
Cinnabar is the chief ore of which element?
AnswerMercury
Cinnabar is mercury sulfide, the main historic source of mercury.
What gas do coal miners call firedamp?
AnswerMethane
Firedamp is methane released from coal seams, which can ignite.
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