mineral

Diopside (likely Chromian Diopside)

Diopside, part of Clinopyroxene family of inosilicates. Chemical formula: CaMgSi2O6. The green variety is often Chromian Diopside due to chromium impurities.

Hardness: 5-6 on Mohs scale. Color: Green (ranging from light green to emerald green, often dark green in beads). Luster: Vitreous (glassy). Crystal Structure: Monoclinic. Cleavage: Good in two directions at nearly 90 degrees. Specific Gravity: 3.22-3.38. Often translucent to opaque when cut into beads.

Hardness: 5-6 on Mohs scale
Luster: Vitreous (glassy)

Identified November 27, 2025More mineral →

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Physical properties

Formation & geological history

Forms in a variety of igneous and metamorphic rocks. Chromian Diopside, specifically, is often found in ultrabasic igneous rocks (like kimberlite, which also hosts diamonds) and high-temperature metamorphic rocks such as skarns, marble, and hornfels, especially those rich in calcium and magnesium. Its formation is typically associated with high-temperature and moderate-to-high pressure conditions. Geological age varies depending on the specific deposit.

Uses & applications

Primarily used as a gemstone, particularly the vibrant green Chromian Diopside, often cut into beads, cabochons, and faceted stones. It's considered an alternative to more expensive emeralds or tsavorites. While not widely used in industry, it is a significant mineral for geological studies due to its presence in mantle rocks and metamorphic environments.

Geological facts

Also known as 'Chrome Diopside' due to its chromium content, which gives it its characteristic green color. High quality specimens can show chatoyancy (cat's eye effect) or asterism (star effect) when cut correctly, though this is less common. It holds some appeal to collectors for its intense color and geological significance. Russia (especially Siberia) is a major source of gem-quality Chromian Diopside.

Field identification & locations

In the field, Diopside can be identified by its green color (especially the vivid green of chromian variety), vitreous luster, and two distinct cleavage planes intersecting at approximately 90 degrees. Its hardness is moderate, meaning it can be scratched by quartz. It's commonly found in metamorphic regions, including contact metamorphic zones (skarns), and in some igneous rocks. Famous localities include Siberia (Russia), Pakistan, Italy, Canada, and the USA.

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