semi-precious

• semiprecious

From semi- +‎ precious.

semi-precious (not comparable)

1. Sort of or somewhat precious or valuable. Usually used as part of the phrase semi-precious stones or semi-precious gems.
   • 2009, Simon Cox, Decoding The Lost Symbol, Simon and Schuster, →ISBN, page 156:

     This semiprecious stone, which resembles green glass, has gemlike qualities and is often used in jewelry.

In modern English, the semi-precious stones are those other than diamond, ruby, sapphire and emerald.

• semi-precious stones
• semi-precious gems

•   gemstone on Wikipedia.Wikipedia