Mineral Species: Diopside

Chemical Formula: CaMgSi2O6

Chemical Name: Calcium Magnesium Silicate

Mineral Class: Inosilicate

Mineral Notes: Diopside is an important rock forming mineral in several metamorphic and basic to ultra basic igneous rocks. It is a part of an important solid solution series of the pyroxene group. The series includes the minerals hedenbergite, CaFeSi2O6, and augite, (Ca,Na)(Fe, Mg,Al)(Al,Si)2O6. Diopside is the magnesium rich end member of the series. The diopside-hedenbergite series is analogous to the amphiobole, tremolite- actinolite series. Diopside has several varieties, including a chromium-rich gem variety called chrome diopside. Violan is rare blue variety found in some localities in Italy. There is also a green "cat's eye" variety that contains minute inclusions, probably of Rutile, that reflect light in such a way as to produce a linear luminscence within the crystal. Still another variety is quite dark, with included Rutile needles aligned to produce a 4-pointedstar, hence the name star diopside. Common Diopside is typically white or green and can have a glassy luster. While the colour of chrome diopside is much brighter, many specimens of common Diopside are also cut for gemstones.

Description: Numerous green Diopside crystals embedded in matrix. The largest is excellently formed, stands up above the matrix and is quite gemmy. Others are smaller and fused together. They have a bright glassy luster.

Location: Glasgruvan, Vastmanland, Sweden.