Gemstones
There is no common definition of a gemstone. Most
gemstones are minerals (e.g. diamonds) or a kind of rock (e.g. onyxes). Sometimes gemstones even include stones which are organic in origin (e.g. amber). They do, however, have one thing in common - they are very pretty and valuable.
Related words:
OnyxRead more:
Gemstone guide,
Diamonds