Chlorastrolite: Gemstones Information
The name chlorastrolite has been used for an opaque ornamental variety of the monoclinic mineral pumpellyite. The ornamental variety forms fibrous aggregates with other minerals and shows green and white patterns. The most desirable pattern resembles tortoiseshell.Some of the green is intense and could be mistaken for one of the jade minerals. However, the RI differs from those of nephrite and jadeite at a mean value of 1.7. The hardness is 5–6 and the SG in the range 3.1–3.5. The crystal system is orthorhombic. Pumpellyite occurs in a number of different environments; most of the chlorastrolite variety occurs in the Lake Superior area of the USA.