What is Native Sulphur?
Native sulphur is a bright yellow orthorhombic element mineral formed around volcanic fumaroles, evaporites and oxidised sulfide deposits.
Mineralogy and crystal structure
Reference formula: S. The stable low-temperature form is orthorhombic alpha-sulfur built from S8 molecules. Sulfur can melt or burn easily, and colour may darken with impurities, so crystal form and locality remain important. Native Sulphur is classified with elements and has a orthorhombic crystal system. Typical hardness is 1.5–2.5 on the Mohs scale and specific gravity is approximately 2.0–2.1.
Colour, lustre and habit
Typical colours include bright yellow, pale yellow, orange. The usual dipyramidal, massive, powdery habit and resinous, vitreous, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Native Sulphur forms in or is associated with volcanic fumaroles, sedimentary evaporites, salt domes and oxidation of sulfide minerals. Important documented localities include Italy, Poland, Bolivia, Mexico, Indonesia, the United States and Chile.
Pure yellow colour from a volcanic vent
Native sulphur is one of mineralogy's clearest colour stories: bright yellow crystals can grow where volcanic gases cool, while evaporite specimens show a completely different geological route to the same element.
Collecting and care
Keep away from heat, flame and strong oxidisers; protect fragile crystals and avoid dust.
