mineral

Spinel

Magnesium Aluminum Oxide (MgAl2O4)

AI-generated identification · may be incorrect

Hardness: 8.0 on Mohs scale; Color: Pink, magenta; Luster: Vitreous (glassy); Crystal structure: Isometric (octahedral); Cleavage: Indistinct; Specific gravity: 3.54-3.63

Hardness: 8
Color: Pink, magenta
Luster: Vitreous (glassy)

Identified May 3, 2026More mineral →

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Physical properties

Hardness: 8.0 on Mohs scale; Color: Pink, magenta; Luster: Vitreous (glassy); Crystal structure: Isometric (octahedral); Cleavage: Indistinct; Specific gravity: 3.54-3.63

Formation & geological history

Formed through regional metamorphism of limestone and dolostone, or as a primary mineral in mafic igneous rocks. It is most frequently found in magnesium-rich marbles.

Uses & applications

Primarily used as a gemstone in jewelry due to its hardness and brilliance. Synthetic spinel is used in refractories and as a blue-colored glass substitute.

Geological facts

Historically mistaken for ruby because they are found in the same mines; the 'Black Prince's Ruby' in the British Imperial State Crown is actually a red spinel.

Field identification & locations

Identify by its octahedral (double pyramid) crystal habit and extreme hardness. Common locations include Myanmar (Mogok), Sri Lanka, Vietnam, and Tajikistan.