What is Spessartine?
Spessartine is the orange manganese-rich garnet, valued as a bright gemstone and as a sharp cubic collector mineral from evolved pegmatites.
Mineralogy and crystal structure
Reference formula: Mn3Al2Si3O12. Spessartine is a cubic garnet end member, but natural material commonly contains pyrope, almandine and other substitutions. Colour saturation, clarity and origin separate gem rough from specimen material. Spessartine is classified with silicates and has a cubic crystal system. Typical hardness is 7–7.5 on the Mohs scale and specific gravity is approximately 4.1–4.3.
Colour, lustre and habit
Typical colours include orange, orange-red, red-brown, yellow. The usual dodecahedral, trapezohedral, granular habit and vitreous lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Spessartine forms in or is associated with granitic pegmatites, rhyolitic rocks, metamorphic rocks and alluvial gem deposits. Important documented localities include Nigeria, Namibia, Tanzania, Mozambique, Brazil, Madagascar and the United States.
Orange fire in the garnet family
Spessartine sells through lively orange colour and strong garnet durability. Bright crystals in a contrasting pegmatite matrix are especially attractive to collectors.
Collecting and care
Clean with warm soapy water and protect from sharp impact. Retain treatment and origin information for valuable faceted stones.
