Native sulphur
Yellow elemental sulphur, found in some carbonaceous chondrites and long argued over as a sign of alteration.
Key facts
- Formula
- S
- Family
- Carbonates, sulphates, salts and weathering products
- Crystal system
- Orthorhombic
What it is
Native sulphur is sulphur in its pure, uncombined form, which crystallises as soft, bright yellow crystals that melt at about 115 °C. It forms where sulphide minerals are oxidised but not all the way to sulphate.
Where it is found
Small crystals have been reported from CI and CM chondrites such as Orgueil. Some appear to have formed on Earth, after the fall, as sulphides reacted with air and moisture; others may have grown on the parent body.
How it is recognised
It is identified by its yellow colour, its softness and its tendency to evaporate under an electron beam. Raman spectroscopy confirms it.
Did you know?
The volcanic moon Io is coloured yellow and orange by sulphur.
Sulphur in carbonaceous chondrites may have been a source of the sulphur in Earth's oceans and life.