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Mineral Properties and Uses

sulfur terminal

Sulfur terminal: Piles of yellow sulfur at a terminal near Vancouver, British Columbia, Canada. The sulfur is brought by rail from oil and natural gas processing facilities in the Province of Alberta. At this terminal it is loaded onto barges and ships for bulk transport. Photo © iStockphoto / teekaygee.

sulfur fumarole

Sulfur fumarole: As hot volcanic gases, rich in sulfur, escape from a volcanic vent, the gases cool and sulfur is deposited as yellow crystals around the vent. This fumarole on the island of Kunashir (in the Kuril Islands, northeast of the Japanese island of Hokkaido) has a significant accumulation of bright yellow sulfur. Photo © iStockphoto / Sergey Dubrovskiy.

Sulfur odor sourcesDid You Know? Many strong odors are produced by sulfur compounds. The smell of skunks, matches, garlic, grapefruit, and rotten eggs are caused by sulfur. Image © iStockphoto / Florintt, Gio_banfi, Abomb Industries Design, ivelly, and Big_Ryan.

What is Sulfur?

Sulfur is an abundant and common element, but it is rarely found in a pure, uncombined form at Earth's surface. As an element, sulfur is an important constituent of sulfate and sulfide minerals. It occurs in the dissolved ions of many waters. It is an important constituent of many atmospheric, subsurface, and dissolved gases. It is also an essential element in all living things and is contained in the organic molecules of fossil fuels.

As a mineral, sulfur is a bright yellow crystalline material. It is found near volcanic vents, where it sublimates from escaping volcanic gases and precipitates from hot spring waters. It is found in small amounts as a weathering product of sulfate and sulfide minerals. The largest accumulations of mineral sulfur are found in the subsurface, associated with the evaporite minerals of salt domes. It is thought to be released from gypsum and anhydrite by bacterial action.

Ancient rocketDid You Know? The Chinese discovered sulfur in about 2000 BC, used it to make gunpowder in the 7th century, and used gunpowder to launch rockets, shoot projectiles, and make hand grenades in the 10th century.

Physical Properties of Sulfur

Chemical Classification Native element
Color Bright yellow
Streak Yellow
Luster Resinous
Diaphaneity Transparent to translucent
Cleavage None
Mohs Hardness 1.5 to 2.5
Specific Gravity 2.0 to 2.1
Diagnostic Properties Yellow color, low hardness, low specific gravity, extremely flammable burning with a blue flame, low melting temperature
Chemical Composition S
Crystal System Orthorhombic
Uses Sulfuric acid, fertilizers, insecticides, fungicides, gunpowder, pharmaceuticals, sulfur compounds
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The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Inexpensive mineral collections are available in the Geology.com Store.

Io sulfur volcanoesDid You Know? Jupiter's moon, Io, has over 400 active volcanoes that emit enormous amounts of sulfur - so much sulfur that the moon has a yellowish color.

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