Almandin

Almandin, also spelled almandine in English, is the iron-rich endmember of the garnet group with the chemical formula Fe3Al2Si3O12. It is part of the pyralspite garnets, which also includes pyrope and spessartine. Almandine garnets are typically deep red to red-violet, sometimes brownish, and may show zoning or inclusions. They crystallize in the isometric system, commonly forming dodecahedra or trapezohedra, and have a hardness of about 7 to 7.5 on the Mohs scale. In gemology, almandine is used as a gemstone and is valued for its color and durability.

Almandine forms in regional metamorphic rocks such as schists and gneisses, produced by metamorphism of silica- and aluminum-rich sediments, and also occurs in some igneous rocks. It is among the most widespread garnet species and is frequently found alongside other garnets and minerals such as mica, staurolite, and sillimanite. Gem-quality material is mined in various localities around the world, including Sri Lanka, Madagascar, Brazil, the United States, Russia, and Tanzania. The name almandin derives from Alabanda, an ancient town in Anatolia, from which the mineral’s name was adopted into mineral nomenclature in the early modern period. In jewelry, deep red almandine stones are commonly cut as cabochons or faceted gems, valued for their color and resilience under normal wear.