Tetragonal

Tetragonal

  

Discovered in 1791 in the lavas of Mount Vesuvius, leucite is a rare mineral that can be found in recent potassium rich mafic and ultramafic lavas. It is found only in silica-deficient rocks and never in rock containing quartz. It is named from the Greek leucos for “white,” in allusion to its common color.

  

Named from two Greek words meaning “front” and “leaf” because of its tendency to exfoliate when ignited, this mineral occurs as a secondary mineral linking cavities in basalt and related rocks.

  

Zircon’s name comes from the Arabic “car”, gold, plus “gun” colored, referring to one of the many colors that the mineral may display. It is found in most igneous rocks as small crystals and as alluvial grains due to its high hardness. When crystals are large enough, it is used as a gemstone.

  

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.”

  

Characterized by its square tabular crystals, orange to yellow color, high luster and association with other lead minerals, wulfenite is found in the oxidized zones of hydrothermal lead deposits. Discovered in 1845, it is named after the Austrian Jesuit mineralogist, Franz Xavier von Wulfen (1728-1805).

  

An ore of tungsten, this mineral was named after Karl Wilhelm Scheele (1742-1786), Swedish chemist, who proved the existence of tungsten oxide in the mineral in 1781. It is found in granite pegmatites, contact metamorphic deposits, and high temperature hydrothermal veins

  

This mineral is characterized by its adamantine luster and red color. Its name is from the Latin rutilus meaning “reddish” and is one of the five forms of titanium dioxide found in nature. Its slender crystals can be found traversing quartz veins forming rutilated quartz. Most of the ore is produced as a coating of welding rods, but is also used to give a yellow color to porcelain and false teeth.

  

One of the most common manganese ore minerals, pyrolusite is used in making steel. It is widespread in its occurrence, forming in lacustrine, shallow marine, and bog deposits. It was named in 1827 from the Greek word for “fire” and “to wash” because it was used to remove brown and green tints in the making of glass.

  

The mineral name is derived from the term “Cassiterides,” which was applied to an island off the western coast of Europe in pre-Roman times. The primary ore of tin, this mineral is found in hydrothermal veins and pegmatites associated with granite intrusions. The chief use of tin is in the manufacture of tin plate and tern plate.