Pure Sulphur is bright yellow. The color may be altered if impurities are present. Clay and selenium impurities, as well as volcanic mixtures in sulfur can cause it to be slightly red, green, brown, or gray. Sulphur often occurs in petroleum deposits, where it is found coated with greasy black petroleum.
Sulphur is soft, light in weight, and very brittle. Care must be exercised when handling and storing specimens. When kept moist or not allowed to dry when wet, hydrogen will mix with the Sulfur, forming hydrogen sulfide (H2S), which causes the deterioration of a specimen.
To prevent this, Sulfur should not be stored under humid conditions. It is best not to wash Sulfur specimens, as warm water can dissolve it. Sulfur also has the tendency to crack when exposed to mild heat, including body heat. It should be handled as little as possible, and kept out of light to avoid cracking.
