ˌprecious ˈstone noun [countable]
a rare and valuable jewel such as a diamond or an emerald ⇒ semi-precious

[TahlilGaran] Dictionary of Contemporary English ▲

jewel a valuable stone, such as a diamond:
He had a large fortune in gold and jewels.
the crown jewels (=the crown and other valuable objects worn by the king or queen on important royal occasions)
a jewel thief
precious stone a rare and valuable jewel such as a diamond or an emerald:
The handle of the sword was decorated with precious stones.
gem (also gemstone) a jewel that has been cut into a special shape:
The cross had large red gems set into it.
Her eyes were shining like gemstones.
semi-precious stone a valuable stone, but one that is not as rare or valuable as a diamond, ruby, emerald etc:
Lapis lazuli is a semi-precious stone that was often used by the ancient Egyptians.
solitaire technical a single jewel, especially a large diamond:
a gold ring with a diamond solitaire

[TahlilGaran] English Thesaurus ▲