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Chemical Formula | S | |||||||||||
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Composition | Sulfur | |||||||||||
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Color | Bright yellow to yellow-brown | |||||||||||
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Streak | White | |||||||||||
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Hardness | 1½ - 2½ | |||||||||||
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Crystal Forms and Aggregates |
(Orthorhombic) Steep bipyramidal and tabular crystals are common, sometimes occurring as hollow skeletons. Small grains, wheat sheaves, and encrustings occur. Massive, earthy specimens are prevalent, and are usually found with bubbly holes throughout their surface. | |||||||||||
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Transparency | Transparent to Opaque | |||||||||||
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Specific Gravity | 2.0 - 2.1 | |||||||||||
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Luster | Adamantine on clean, clear crystal surfaces, otherwise resinous or dull | |||||||||||
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Cleavage | 3,2 | |||||||||||
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Fracture | Conchoidal | |||||||||||
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Tenacity | Brittle | |||||||||||
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Other ID Marks | 1) Cracks when exposed to heat 2) Dissolves in warm water 3) May have a greasy feel 4) Gives off a mild, rotten egg-like odor. Odor becomes strong if heated |
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Other Names |  Native Sulfur, Sulphur,
Native
Sulphur,  Brimstone |
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Polymorphs | Rosickyite or Rosickyite - Monoclinic form of sulfur | |||||||||||
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In Group | Native elements ; Nonmetallic elements | |||||||||||
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All About | Pure
Sulfur 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. Sulfur often occurs
in petroleum deposits, where it is found coated with
greasy black petroleum. Sulfur crystallizes in the orthorhombic system, but an uncommon monoclinic form of sulfur also exists. This monoclinic form is scientifically considered a different mineral than Sulfur, and is scientific name is Rosickyite. Most dealers selling Rosickyite usually label the mineral as "Monoclinic Sulfur". The earthy, massive, specimens usually come from volcanic sulfur springs, and have small, bubbly holes throughout. These specimens usually have a greasy feel, and exhibit a strong "rotten-egg" odor. Much of the fine Sulfur specimens have been destroyed by mining operations. Underground Sulfur deposits are flooded with hot water, causing the Sulfur to melt into a brine. The brine is pumped to the surface, where the water is evaporated and the sulfur recovered. Such mining operations destroy all specimens. Sulfur is soft, light in weight, and very brittle. Therefore, 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. (See Storing minerals for more information). It is best not to wash Sulfur specimens, as warm water will dissolve it. Sulfur also the tendency to crack when exposed to even mild heat, including body heat. It must be handled as little as possible, and kept out of light to avoid it from cracking. |
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Uses | Sulfur is a fairly common element, with many
uses. Although most sulfur is extracted from sulfides, Native Sulfur, being common, is also used
as a source. The fine specimens from Agrigento and
Cattolico in Sicily, Italy, are highly sought by mineral
collectors. Sulfur has many industrial uses. It is used in the manufacture of black powder, matches and explosives. It is also used to create rubber, in dyes, and as an insecticide and fungicide. It is also used in the manufacturing of sulfuric acid. |
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Striking Features | Color, softness, very low density, and habit of cracking when exposed to heat | |||||||||||
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Complex Tests | Melts at only 226° F (108° C) and gives off a blue flame with fumes that smell like rotten eggs | |||||||||||
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Popularity (1-4) | 1 | |||||||||||
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Prevalence (1-3) | 1 | |||||||||||
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Demand (1-3) | 1 | |||||||||||
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Distinguishing Similar Minerals |
Due to its interesting properties, Sulfur is easily distinguishable from all minerals | |||||||||||
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Commonly Occurs With |
Realgar, Cinnabar, Barite, Celestine | |||||||||||
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Noteworthy Localities |
The most famous specimens, well crystallized and brightly colored, come from Agrigento and Cattolico, Sicily, Italy. Similar specimens exist in Louisiana and Texas, but the industrial mining methods destroys them all. Sulfur deposits exist in Bex, Switzerland; Cadiz, Spain; and Malvesi, France. Most Sulfur is formed in volcanoes, and therefore many deposits are mined at extinct volcanoes throughout the world. One such deposit is in San Felip, Baja California, Mexico. In the U.S., deposits containing specimens are found in Lassen Peak, Tehama Co., California; Sulphurdale, Beaver Co., Utah; Sulphur Bank, Lake Co., California; and in Yellowstone National Park, Wyoming. | |||||||||||
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Picture Icon Links |
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Picture Links | 1. Crystal fragment of Sulfur 2. Small rounded Sulfur crystals 3. Glassy rounded Sulfur crystals on rock 4. Massive bubbly Sulfur |
