loose stone; unset jewel
Jewelry term for a gemstone that is not mounted in a setting. Used in trade and collecting contexts.
See also: 裸石
I plan to have this loose stone set into a ring later.
I was shown several loose stones at the jewelry store.
I had this diamond loose stone set into a ring mounting.
I bought the sapphire as a loose stone and had it set later.
From English 'loose', used in the jewelry sense of 'loose stone'.