From Longman Dictionary of Contemporary Englishsemi-preciousˌsem‧i-ˈprecious British English, semiprecious American English /ˌsemiˈpreʃəs◂/ adjective DCJa semi-precious jewel or stone is valuable, but not as valuable as a diamond, ruby etc
Examples from the Corpus
semi-precious• Inside the bottle you will find a handful of sparkling semi-precious gemstones which spiritual healers believe affect our health and well-being.• Diamonds, emeralds, rubies and sapphires as well as a mixture of semi-precious stones glinted and sparkled at her from all directions. 