NATIVE SULFUR

Chemistry: S , Elemental Sulfur
CLASS: Elements
Uses: Major ore of sulfur which is used for chemical production
Specimens

Sulfur, which is given a bad reputation because of its odor, can make a very beautiful mineral specimen, and fine quality examples are much sought after. The unmistakable deep yellow color is not matched by any other mineral and the nicely shaped crystal forms of sulfur add to its attractiveness. As for the odor, this occurs when water mixes with the sulfur and a small amount of hydrogen sulfide (H2S) gas is produced. Although only small amounts of H2S form from just moisture in the air, it is a powerful odor producer and is the dominating contributor to the odor of rotten eggs. Rest assured, though, that most specimens of sulfur, when kept dry, do not emit a strong odor and this is not difficult for collectors of fine sulfur specimens to ensure.

PHYSICAL CHARACTERISTICS:

Color is a strong yellow color in thick crystals and duller yellow in small crystals to pale yellow in massive or powdery forms. Can also be reddish or greenish yellow with impurities.
Luster is vitreous to more often resinous or earthy in massive forms.
Transparency is transparent to translucent.
Crystal System is orthorhombic; 2/m 2/m 2/m
Crystal Habits include mostly massive or powdery forms but well shaped blocky crystals are common. Crystals can be made up of two dipyramids, one with steeper faces than the other, prisms and/or pinacoids in various combinations.
Cleavage is very poor in two directions.
Fracture is conchoidal.
Streak is yellow.
Hardness is 2.
Specific Gravity is 2.0 - 2.1 (well below average)
Associated Minerals are celestite, calcite, aragonite and gypsum.
Other Characteristics: odor (see above), poor heat conductivity makes it brittle when heated and can actually crack if held tightly in a person's hand.
Notable Occurrences include Michigan and Ohio, USA; Sicily; Poland and Chile.
Best Field Indicators are color, odor, heat sensitivity, lack of good cleavage and crystal habit.