What is Xitieshanite?
Xitieshanite is a hydrated iron chloride sulfate from strongly oxidised mine environments, usually occurring as delicate yellow crusts or small crystals.
Mineralogy and structure
Reference formula: FeClSO4·6H2O. Xitieshanite is monoclinic and strongly hydrated. COD 9015783 provides an exact FeClSO4·6H2O structural reference; humidity can alter fragile specimens. Xitieshanite is classified with sulfates and has monoclinic crystal symmetry. Typical hardness is 2–3 on the Mohs scale and specific gravity is approximately 2.2–2.5.
Colour, lustre and habit
Typical colours include yellow, yellow-brown, greenish yellow, brown. The usual prismatic, fibrous, crusty habit and vitreous, pearly, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Xitieshanite forms in or is associated with oxidised polymetallic ore deposits, mine workings and chloride-sulfate-rich secondary zones. Important documented localities include the Xitieshan deposit in Qinghai, China, the United States, Chile and other arid oxidation environments.
Yellow sulfate chemistry from a mine oxidation zone
Xitieshanite records the aggressive chemistry of mine oxidation. Its commercial appeal is strongest as a fresh, well-labelled microcrystal rather than a handled loose powder.
Collecting and care
Keep sealed and dry, avoid water, acids and dust, and handle fragile crusts minimally.
