spineliin
Spineliin is a rare and unusual mineral that belongs to the spinel group. It is primarily composed of magnesium aluminum oxide, with the chemical formula MgAl2O4. Spineliin is known for its distinctive deep blue to black color and its high refractive index, which gives it a strong, brilliant appearance. It is typically found in metamorphic rocks, particularly in serpentinites and other magnesium-rich environments. Spineliin is also notable for its hardness, which is relatively high on the Mohs scale, making it resistant to scratching.
The mineral was first described in the late 19th century and has since been studied for its