Hexagonal

Hexagonal

The most common and abundant of all the minerals, quartz is a significant component of many igneous, metamorphic, and sedimentary rocks. It is found in an impressive range of varieties and colors; the purple variety is amethyst, which gets its color from small amounts of ferric iron; the yellow variety is called citrine; while the dark variety, smoky quartz, is formed from exposure to radioactive material. The name is a German word of ancient derivation.

A rock-forming mineral, nepheline is common in silica-deficient igneous rocks. Discovered in 1801 in the lavas of Mount Vesuvius, Italy, this mineral is characterized by its greasy luster. The name comes from the Greek word meaning “a cloud” because when immersed in acid, the mineral becomes cloudy.

A member of the tourmaline group of minerals, tourmaline was "discovered" in the early 1800s that some of the "zircons" arriving in European gem centers from the far east were actually a previously undescribed mineral. This mineral can be identified by its hexagonal crystals and hardness. Famous localities for the occurrence of gem varieties include Minas Gerais, Brazil, Ural Mountain, and Madagascar.

Readily identified by its hexagonal crystals, this mineral is commonly found in pegmatites. It was named after the Greek beryl, which referred to a number of blue-green stones in antiquity. The largest beryl crystal reported (unconfirmed) was 18 m long and 3.5 m wide from Malakialina, Madagascar.

Found in granite pegmatites and schists, this mineral was named in 1833 by Nordenskiold from the Greek word for "deceiver," in allusion to its being mistaken for quartz. It is occasionally cut as a gemstone.

An ore of zinc, this mineral was named after James Smithson (1754-1829), a British chemist and mineralogist and founder of the Smithsonian Institution. It commonly occurs in botryoidal forms and in a variety of colors including yellow, blue, pink, and purple.

Siderite is an ore of iron when found in sufficient volume to be economically recoverable. It was named in 1845 from the Greek word meaning "iron," in allusion to its composition. It is most often found in bedded sedimentary deposits with shales and coal beds and also as bog deposits.

Discovered in 1813, this pink mineral occurs in low to moderate temperature hydrothermal veins, metamorphic deposits, carbonates, and sedimentary deposits. Its name comes from the Greek, "rose" and "coloring" referring to its color.

Discovered in 1808, this mineral was named in allusion to the composition, containing principally Magnesium. It is a member of the calcite mineral group and occurs primarily in igneous and sedimentary rocks.

The name of this mineral reflects its vanadium content. It is a rare secondary mineral found in the oxidized portion of lead veins. It was first discovered by Señor A.M. del Rio (1764-1849), a professor at the School of Mines of Mexico, Zimapan, before the element vanadium was discovered in 1830.