Diopside (CaMgSi₂O₆) is the calcium-magnesium end-member of the pyroxene group, one of the most abundant mineral families in Earth’s crust and mantle. It forms in contact-metamorphic skarns, regional metamorphic rocks, and peridotite xenoliths brought up by volcanic eruptions. Crystallographic-quality Diopside specimens favor sharp prismatic crystals on white calcite-marble matrix; chrome diopside (with Cr³⁺) yields brilliant emerald-green gem material from Siberia and East Africa. China hosts notable skarn-type Diopside in Sichuan and Liaoning.
Key Facts
- Mohs hardness 5.5–6.5.
- Monoclinic; classic prismatic crystals with characteristic ~87° prism cleavage angles.
- Color most commonly white-green to gray-green; chrome-bearing material is bright emerald.
- Diopside-augite series — continuous solid solution toward iron-rich and aluminum-rich pyroxenes.
- Member of the clinopyroxene branch alongside augite, hedenbergite, and aegirine.
Notable Chinese Localities
Sichuan skarn deposits and Liaoning contact-metamorphic zones produce collector specimens. Outokumpu (Finland) yields chrome diopside; De Kalb (NY) supplies American material.
Found at these Localities
- Merelani Hills (梅雷拉尼山(坦桑石产地))
- Sichuan (四川)
