Thuparlial

Thuparlial, also known as prehnite, was a hard, tough gemstone which varied in color from rich green through pale greenish yellow and yellow to brown.

Description
This ornamental stone was translucent and cut in facets if light-colored but otherwise cut cabochon. It was abundant in hardened lavas as crust lining gas cavities in the rock, but only rarely was this crust thick enough or colorful enough to be cut into gemstones. A typical stone had a base value of 10 gp.