What is Stichtite?
Stichtite is a soft pink to lilac hydrated magnesium chromium carbonate, popular as an ornamental stone and valued for vivid colour and serpentine associations.
Mineralogy and crystal structure
Reference formula: Mg6Cr2CO3(OH)16·4H2O. Stichtite is a layered hydrated carbonate with variable chromium and magnesium. It is soft, commonly massive and often sold as polished material; the selected COD model represents the trigonal structure. Stichtite is classified with carbonates and has a trigonal crystal system. Typical hardness is 1.5–2 on the Mohs scale and specific gravity is approximately 2.1–2.3.
Colour, lustre and habit
Typical colours include lavender, pink, purple, lilac, grey. The usual massive, botryoidal, vein habit and waxy, pearly, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Stichtite forms in or is associated with hydrothermal alteration and weathering of ultramafic rocks, commonly with serpentine. Important documented localities include Tasmania, Australia, South Africa, Canada and Zimbabwe.
Lilac colour from an ultramafic alteration zone
Stichtite is commercially effective because its soft lilac colour contrasts beautifully with dark serpentine matrix. Its value is visual and geological, not a claim of therapeutic effect.
Collecting and care
Avoid water, acids, heat and scratches. Clean with a soft dry or slightly damp cloth and do not use ultrasonic or steam cleaning.
