gem
US /dʒem/
UK /dʒem/

1.
a precious or semiprecious stone, especially one cut and polished for use in jewelry.
:
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The necklace was adorned with sparkling gems.
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She inherited a beautiful sapphire gem from her grandmother.
2.
a person or thing considered to be outstandingly good or special of its kind.
:
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This restaurant is a hidden gem.
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She's a real gem, always helping others.