Minerals

Used in ceramics and as a mild abrasive, microcline is one of the most common feldspar minerals. It can be colorless, white, cream to pale yellow, salmon pink to red, or bright green to blue-green. Microcline forms short prismatic or tabular crystals that are often of considerable size: single crystals can weigh several tons and reach yards in length. Crystals are often multiply twinned, with two sets of fine lines at right angles to each other. This gives a “plaid” effect that is unique to microcline among the feldspars.

The most common pyroxene, augite is named after the Greek word augites, which means “brightness”—a reference to its occasional shiny appearance. Most augite has a dull, dark green, brown, or black finish. Augite occurs chiefly as short, thick, prismatic crystals with a square or octagonal cross section and sometimes as large, cleavable masses. It occurs in a solid-solution series in which diopside and hedenbergite are the end-members. Augite is common in silica-poor rocks and various other dark-colored igneous rocks, as well as igneous rocks of intermediate silica content. It also occurs in some metamorphic rocks formed at high temperatures (1,065°F/575°C or above). Augite is a common constituent of lunar basalts and some meteorites. Notable crystal localities are in Germany, the Czech Republic, Italy, Russia, Japan, Mexico, Canada, and USA. Because it is difficult to distinguish between augite, diopside, and hedenbergite in hand specimens, all pyroxenes are often identified as augite.

A Gemstone Forged by Earth’s Hidden Forces Amethyst is more than a beautiful purple gemstone — it is a geological story written in quartz crystals,...

The barium sulfate barite takes its name from the Greek word barys, which means “heavy” a reference to its high specific gravity. It has also been called heavy spar. Barite crystals are sometimes tinged yellow, blue, or brown. Golden barite comes from South Dakota. Crystals are well formed, usually either prismatic or tabular.

Possibly the earliest ore of copper, malachite is believed to have been mined in the Sinai and eastern deserts of ancient Egypt from as early as 3000 BCE. Single crystals are uncommon; when found, they are short to long prisms.

Beryl is a member of cyclosilicate minerals with composed of beryllium aluminium. Chemical formula: Be3Al2Si6O18. Few people have ever heard of the mineral beryl but almost everyone has heard of its principal gemstone varieties emerald and aquamarine.

Five percent of Earth’s crust is made up of iron. Native iron is rare in the crust and is invariably alloyed with nickel. Low-nickel iron (up to 7.5 percent nickel) is called kamacite, and high-nickel iron (up to 50 percent nickel) is called taenite. Both crystallize in the cubic system. A third form of iron-nickel, mainly found in meteorites and crystallizing in the tetragonal system, is called tetrataenite. All three forms are generally found either as disseminated grains or as rounded masses. Kamacite is the major component of most iron meteorites. It is found in most chondritic meteorites, and occurs as microscopic grains in some lunar rocks. Taenite and tetrataenite are mainly found in meteorites, often intergrown with kamacite. Iron is also plentiful in the Sun and other stars.

Sphalerite mineral is in group of Sulfide mineral that is formula ((Zn, Fe)S).It is the principal ore of zinc. Pure sphalerite is colorless and...

Azurite is not a common or abundant mineral, but it is beautiful and its blue color attracts attention. It has been used by people in many parts of the world for thousands of years. Ancient people used it as an ore of copper, as a pigment, as a gemstone, and as an ornamental stone. It is still used for all of these purposes today

Copper was probably the first metal to be used by humans. Neolithic people are believed to have used as a substitute for stone by...

Well developed crystals of epidote, Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH), crystallizing inside the monoclinic system, are of frequent prevalence: they're normally prismatic in dependancy, the course of elongation being perpendicular to the single plane of symmetry.

Bornite, commonly referred to as "peacock ore," is a captivating mineral known for its striking and iridescent appearance. This mineral, composed primarily of copper...