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Types of minerals in geology

Many minerals are coveted around the world for their hanging beauty, rarity, and gem quality. But what is a mineral?

Minerals are fashioned naturally through geological processes. A mineral is a homogeneous strong that can be made of a single native issue or more commonly a compound. Minerals make up Earth's rocks and sands, and are a vital aspect of soils.

5 traits required of all minerals

  1. Be naturally-occurring (man-made materials such as metal are no longer minerals)
  2. Be Inorganic (not living, or from vegetation or animals)
  3. Be stable at room temperature (usually)
  4. Have a common ordered inner shape (atoms have an orderly, repeated geometric pattern) which typically types crystals
  5. Have a precise chemical composition (may range inside given limits) that is the identical in all places the mineral occurs

Fundamental Concepts

  • Nonsilicate minerals: A mineral except silicon (Si).
  • Silicate: Refers to the chemical unit silicon tetroxide, SiO4, the indispensable constructing block of silicate minerals. Silicate minerals make up most rocks we see at the Earth's surface.

Physical Properties

Minerals are recognized and described in accordance to their bodily homes of:

  1. Cleavage: The tendency of a mineral to spoil (cleave) alongside vulnerable planes.
  2. Color: Most minerals have an awesome color whilst others are variable in color.
  3. Hardness: A measure of a mineral's resistance to scratching. This is measured by scratching it towards some other substance of acknowledged hardness on the Mohs Hardness Scale
  4. Luster: The reflection of mild from the floor of a mineral, described through its fantastic and intensity. Luster is described as metallic, glassy, dull, earthy, etc.
  5. Streak: refers to the color of the residue left by way of scratching a mineral on a tile of unglazed porcelain, like a piece of chalk.
  6. Specific gravity: the ratio of the density of a mineral to an equal extent of water.

Related: Golden Gate National Recreation Area, California

To many, the National Park System is one of America's favorite mineral collections which can be seen in quite a number of rock formations and elements around the country.

Natural objects, such as rocks and minerals, make a contribution to the splendor and wonderment of the National Parks and ought to be left, as they have been found, so that others can journey an experience of discovery.

Common Minerals


Quartz is one of the most frequent minerals in the Earth's crust. It is made of silicon dioxide (SiO2), in any other case recognised as silica. Varieties of quartz based totally on shade include: amethyst (purple), smoky quartz (gray), rose quartz (pink), and citrine (yellow-green). Quartz has a glassy luster and a hardness of 7.

Quartz happens in all three rock kinds and and can be considered in parks such as:
  • Glacier National Park, Montana
  • Black Canyon of the Gunnison National Park, Colorado
  • Great Smoky Mountains National Park, North Carolina
Potassium feldspar
Potassium feldspar (or alkali feldspar or K-spar) is a member of the feldspar mineral household and is a silicate mineral. It includes a huge quantity of potassium and is usually pink-salmon to white in color. Potassium feldspar has a hardness of 6. The crystals are stubby prisms and have a streaky look referred to as perthitic texture (as considered in picture on the left).

A large quantity of potassium feldspar is discovered in the slope sediments and granite at:

  • Acadia National Park, Maine 
Plagioclase feldspar
Plagioclase is a member of the feldspar mineral family. Plagioclase feldspars are but any other silicate that includes significant sodium or calcium. Plagioclase crystals are stubby prisms, typically white to gray and have a glassy luster.
Plagioclase feldspar can be determined in the igneous and metamorphic rocks at:
  • Grand Teton National Park, Wyoming
  • City of Rocks National Reserve, Idaho
Micas are every other crew of silicate minerals composed of various quantities of potassium, magnesium, iron, aluminum, silicon and water. All micas structure flat, sheet-like crystals that peel aside alongside one cleavage plane into easy flakes. Biotite (pictured to the left) is a black or brown mica; muscovite is light-colored or clear mica. Mica is so tender (2.5 on Mohs scale) that it can be scratched with a fingernail.

Mica normally takes place in metamorphic and igneous rocks. Biotite and muscovite are two of the major minerals in the metamorphic rocks at:

  • Mount Rushmore National Monument, South Dakota
The amphiboles are a household of silicate minerals that structure prism or needle-like crystals. Amphiboles are normally darkish coloured and include iron, calcium, and aluminum. Hornblende is the most frequent amphibole and is dark inexperienced to black in color. Amphiboles are frequent in igneous and metamorphic rocks.

Amphiboles can be observed in the intrusive igneous our bodies at:

  • Denali National Park and Preserve, Alaska 

and in the metamorphosed gneiss at:

  • Weir Farm National Historic Site, Connecticut
Olivine [(Fe, Mg)2SiO4] is a silicate mineral containing iron and magnesium. It is a green, glassy mineral that types at excessive temperatures. It is frequent in basalt and ultramafic rocks. Gem-quality olivine is known as peridot. A rock made up absolutely of olivine is referred to as dunite. Olivine most normally happens in igneous rocks and can be observed in andesite at:
  • Mount Rainier National Park, Washington
  • Devils Postpile National Monument, California

As properly as in basalt at:

  • Yosemite National Park, California
Talc (Mg3Si4O10(OH)2) is the softest recognised mineral and can be scratched with a fingernail. Upon contact, talc has a one of a kind greasy sense and a waxy/pearly luster. Talc is a foliated mineral and related with metamorphic rocks. It is an alteration product from the metamorphism of minerals such as serpentine, pyroxene and amphibole. Talc can be discovered in talc schist at:
  • George Washington Memorial Parkway, District of Columbia, Maryland, and Virginia 
  • National Capital Parks - East, District of Columbia
Calcite is made of calcium carbonate (CaCO3). Generally white to clear, calcite is effortlessly scratched with a knife. Due to the presence of carbonates (CO3), calcite reacts to most acids (such as hydrochloric acid, HCl) and effervesces on contact. Most seashells are made of calcite or related minerals. Calcite can be observed in many cave and karst formations such as the calcite elements at:
  • Jewel Cave National Monument, South Dakota
  • Wind Cave National Park, South Dakota
Fluorite (CaF2) is viewed to be one of the most colorful minerals in the world. Common hues of fluorite consist of purple, green, yellow, and blue. Fluorite is additionally seen below ultraviolet light, a property that receives its name, fluorescence, from the mineral. Fluorite is regularly unsuitable for quartz however it has a lower hardness of four Fluorite is the nation mineral of Illinois which was once as soon as the biggest fluorite producer in the United States.