Almandine, also known as almandite, is a species of mineral belonging to the garnet group. The name is a corruption of alabandicus, which is the name applied by Pliny the Elder to a stone found or worked at Alabanda, a town in Caria in Asia Minor. Almandine is an iron alumina garnet, of deep red color, inclining to purple. It is frequently cut with a convex face, or en cabochon, and is then known as carbuncle. Viewed through the spectroscope in a strong light, it generally shows three characteristic absorption bands.
Almandine
A 19th-century almandine garnet brooch
Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.
Garnet
A sample showing the deep red color garnet can exhibit.
Crystal structure of pyrope garnet. White spheres are oxygen; black, silicon; blue, aluminium; and red, magnesium.
Same view, with ion sizes reduced to better show all ions