Spinel

This sample of spinel is displayed in the Smithsonian Museum of Natural History. Spinel is an oxide of magnesium and aluminum with the composition MgAl₂O₄ . This sample is about 8x8 cm and is from Antanimora, Madagascar.

This sample of spinel is from Orange County, New York. It is formed with hornblende and measures about 5x5 cm.