Black spinel stone is a rare gemstone made up of hard vitreous magnesium aluminium oxide or magnesium aluminate. Specifically, black spinel is one of the rarest minerals that comes from the Spinel family and is a true gemstone often confused with black tourmaline. It’s said that the name ‘Spinel’ comes from the Latin, ‘spina’ meaning thorn – this refers to the sharp crystal formations it’s made up of.