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Roger Weller, geology instructor
sulfur (also spelled sulphur)
Chemical Group: native element
Chemical Formula: S
Color: sulfur yellow, straw yellow, honey yellow, yellowish brown, yellowish gray
Hardness: 1.5 to 2.5
Specific Gravity: 2.05 to 2.09
Fracture: conchoidal to uneven
Luster: resinous Tenacity: brittle
When rubbed, becomes negatively charged
Crystal Forms: Orthorhombic
Crystals are acute pyramidal; also thick tabular.
Mineral Associations: Sulfur is found in volcanic fumaroles, also by the decomposition of sulfide ores.
Identifying Characteristics: sulfur burns and produces SO2
Uses: many chemical processes, including the vulcanization of rubber.
Occurrences: Sicily, Mexico, Texas
Toxicity: when-swallowed- moderate when inhaled- moderate
Additional Information: A crystal of sulfur can be cracked by the heat from your hand.