What is Sugilite?
Sugilite is a rare purple manganese-bearing silicate, valued as an ornamental stone and collector mineral for saturated colour and attractive matrix patterns.
Mineralogy and crystal structure
Reference formula: KNa2(Fe,Mn,Al)2Li3Si12O30. Sugilite is a hexagonal mineral with variable manganese, iron, aluminium and sodium. The strongest purple colour is highly sought after, while opaque material is commonly cut as cabochons. Sugilite is classified with silicates and has a hexagonal crystal system. Typical hardness is 5.5–6.5 on the Mohs scale and specific gravity is approximately 2.7–2.8.
Colour, lustre and habit
Typical colours include purple, violet, magenta, pink, brown. The usual massive, granular, vein habit and vitreous, waxy lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Sugilite forms in or is associated with manganese-rich metamorphic rocks, altered volcanic rocks and hydrothermal veins. Important documented localities include South Africa, Japan, Canada, India and documented lapidary localities.
Purple colour with a geological signature
Sugilite is commercially distinctive because its saturated purple is tied to an unusual manganese-bearing silicate rather than a simple dyed surface. Pattern, colour consistency and provenance matter in polished material.
Collecting and care
Protect from scratches, acids and prolonged heat. Clean with a soft damp cloth and preserve locality and treatment information for valuable material.
