Luriyl

Luriyl, also known as apatite, was a soft stone, easily worked and widely used throughout the Realms.

Description
Found in crystals, these semi-precious stones yielded attractive faceted gems of vivid yellow, green, yellow-green, and (rarely) blue and purple. Large specimens of blue or purple commanded high prices and were much used in necklaces, pendants, belts, and insets in gowns or cloaks. A typical specimen had a base value of 50 gp.