Sulfides

Sulfides

Named in 1845 in honor of the English mineralogist ( ) William Miller (1801-1880) ( ) who first studied the crystals, this mineral forms as a low-temperature mineral often in cavities and as an alteration of other nickel minerals. It is commonly found as radiating and jack-straw clusters of shiny metallic acicular crystals, pale brass-yellow with an iridescent tarnish.

Characterized by its cockscomb form, this mineral was named in 1845 after an Arabic or Moorish name applied to pyrite and similar metallic bronze-colored minerals. It is frequently found replacing organic matter, forming fossils, and in sedimentary beds, particularly coal beds.

Discovered in 1840, this mineral was named for Lord Greenock (1783-1859). It is the most common mineral containing cadmium, but it is found only in a few localities and in small amounts, usually as an earth-coating on zinc ores, especially sphalerite. Cadmium is used in alloys for antifriction bearings, low-melting alloys, and in electroplating.

Easily recognized by it good cleavage, high specific gravity, softness, and lead-gray streak, this mineral is the primary ore mineral of lead. It is a very common sulfide that has been worked for its lead content as early as 3000 BC. The name is derived from the Latin galena, a name originally given to lead ore.

Discovered in 1832 and named after Niccolo Covelli (1790-1829), an Italian mineralogist and discoverer of the mineral at Mount Vesuvius, this mineral is characterized by its indigo-blue color. It is usually found as a secondary copper mineral in copper deposits and rarely occasionally as a volcanic sublimate.

This mineral is easily recognized by its red color and scarlet streak, high specific gravity, and cleavage. It is a low temperature hydrothermal mineral and the only important source of mercury. The name is from the Persian possibly meaning "dragon's blood."

A major ore of copper, chalcopyrite is the most abundant of the copper-bearing minerals. It is a primary mineral in hydrothermal veins and the principal copper mineral of porphyry-copper deposits. This mineral is easily recognized by its brass-yellow color and greenish-black streak. Its name is derived from the Greek word meaning "copper" and from "pyrites" meaning “strike fire.”

Once of the most important copper-ore minerals, chalcocite occurs as a secondary mineral in or near the oxidized zone of copper sulfide deposits. Under surface conditions, the primary copper sulfides are oxidized, the soluble sulfates formed move downward reacting to form chalcocite, and thus, enriching the ore in copper. The water table is the lower limit of the zone of oxidation and here a "chalcocite blanket" may form.

Known as the "peacock ore" due to it quickly tarnishing to an iridescent purple after exposure to air and moisture, this mineral has been known since 1725, but was not given its current name until 1845 when it was named for Ignaz von Born (1742-1791), an Austrian mineralogist. A widely occurring copper ore, it is usually found associated with other copper minerals in hypogene deposits.

This is the most common mineral containing arsenic and is the principal source of arsenic. It occurs in high temperature gold-quartz or tin hydrothermal veins, pegmatites, and metamorphic rocks. Its name is a contraction of the older term: arsenical pyrite.