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What are gems?
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Gems are stones found in the Earth's crust, used in jewellery. Most are mineral crystals. Diamond is made from carbon. Sapphire is made from corundum. Opal is a gem made from silica, which does not form a crystal. | | A diamond |
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Previous:
Back
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Book:
1001
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Section:
Earth
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Chapter:
Rocks and Minerals
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