Diopside
Image: Didier Descouens (CC BY-SA 3.0)
Mineral NameDiopside
Chemical FormulaCaMgSi2O6
Mohs Hardness5.5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
CleavageGood in two directions at nearly 90 degrees (87 and 93 degrees)
Fractureconchoidal
Specific Gravity3.27
Colorsblack
Transparencyopaque
Type LocalityIndia
Mineral GroupSilicates
Usesjewelry, collector
Associated Mineralsolivine, plagioclase, phlogopite, spinel, garnet, calcite
Rarityuncommon
Description
This image displays a polished black diopside cabochon, exhibiting a prominent four-rayed asterism, characteristic of 'star diopside'. The stone has a smooth, domed surface that reflects light to create the star effect.
Geological Context
Diopside is a common mineral found in various metamorphic rocks, particularly in contact metamorphic zones and skarns formed from the metamorphism of impure dolomitic limestones. It also occurs in some igneous rocks, including ultramafic rocks and kimberlites.
