Spinel
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameSpinel
Chemical FormulaMgAl2O4
Mohs Hardness8
Crystal Systemcubic
Lustervitreous
Streak Colorwhite
Cleavageindistinct/none
Fractureconchoidal
Specific Gravity3.6
Colorsred, pink, orange, blue, violet, black, green, brown
Transparencytransparent
Type LocalityLuc Yen, Yenbai Province, Vietnam
Mineral GroupOxides
Usesjewelry, collector
Associated Mineralscalcite, dolomite, phlogopite, chondrodite, corundum
Rarityuncommon
Description
The image displays a beautiful, well-formed rose-red spinel crystal, approximately 1.6 cm in size, set against a contrasting matrix. Its sharp, octahedral form is clearly visible.
Geological Context
Spinel typically forms in metamorphic rocks, particularly marbles and gneisses, often as a result of contact or regional metamorphism of impure limestones or dolomites. It can also occur in some igneous rocks and as detrital grains in placers.
