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Gemstone Crystal System Density Hardness Refractive index Treatments
monoclinic 3.29 5-6 1.675-1.701 none




A beautiful deep green as shown by the rough crystal above is the most often seen faceted version of this gemstone. Diopside also offers a classic four rayed star stone that is very much like a black star sapphire...with the exception that the sapphire will have a 6 rayed star.

Clarity: Transparent to Opaque
Optic Character:
DR Biaxial positive, AGG
Cause of Color: Fe in most green and brown stones; Cr in some green stones; Violane: Mn
Fluorescence: Green stones can fluoresce with LW; others Inert
Fracture : Concoidal
to uneven
Luster : Vitreous to resinous
Cleavage :
Two direction; perfect
Durability: Poor

Characteristics for Identification:
In star stones: 4 rays

India, South Africa, Finland ,Burma, Madagascar and Italy

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a calcium magnesium silicate

Diopside is a calcium magnesium silicate that crystallizes from magmas. It is usually a fairly uninteresting component of igneous rocks, but there are a few varieties that have gemological merit. The first is a chatoyant (cat's-eye effect) variety. Occasionally, stones have been found that are chatoyant in two directions forming a four pointed star. Ancient civilizations believed that star stones housed living spirits who were looking at you through those stars. My favorite examples of diopside are chrome bearing stones which are vibrant green and transparent. These are found in Russia and East Africa. There is another variety, termed violane, that is bluish violet, used for beads and inlay work.

This gemstone is often confused with:

Chrome Tourmaline
Tsavorite Garnet
Fancy Sapphires
Lab Garnets (Y.A.G.)

chrome diopside