Spinel

Spinel MgAl₂O₄ (purplish gray), with Chondrodite (orange brown) and Norbergite (darker brown), Limecrest Quarry, Sussex Co., New Jersey

Spinel MgAl₂O₄ (purplish gray), with Chondrodite (orange brown) and Norbergite (darker brown), Limecrest Quarry, Sussex Co., New Jersey

Spinel MgAl₂O₄ (purplish gray), with Fosterite (gold), Calcite, Tazheranskii Massif, Lake Baikal Area, Irkutskaya Oblast, Prebaikalia, Russia Ex Renauld Vochten

Spinel MgAl₂O₄ (black), with Quartz, Chalcopyrite, Location Unknown, Ex A.E. Seaman Museum