Microcline

Microcline is a very common mineral from the group of the feldspars within the mineral class of silicates with the chemical formula K [ AlSi3O8 ]. Its color varies from colorless, white to gray, yellow, red and green when amazonite. The transparent to translucent, solidifying in the triclinic crystal system crystals have a vitreous luster.

Etymology and history

Was first found microcline 1830 at Stavern in Norway and described by August Breithaupt, the μικρός the minerals by the Greek words Mikrós for " small" and κλίνειν klin for inclined named due to the characteristic that the cleavage planes show small deviations from 90 °.

Classification

In the old ( 8th edition ) and new classification of minerals according to Strunz ( 9th edition ) of the microcline is part of the Department of framework silicates ( tectosilicates ).

The new, revised Strunz'sche Mineral classification divided here but now more precisely following the absence or presence of zeolitic water of crystallization, and the presence, other anions. According to its composition, which contains no other anions and no water of crystallization than silicon and aluminum, we find the microcline in the subdivision of " framework silicates ( tectosilicates ) without zeolitic H 2 O, without other anions " and there in the feldspar group with the system no. 9.FA.30 and the other members adularia, anorthoclase, Buddingtonit, celsian, Hyalophane, Kokchetavit, Monalbit, orthoclase, sanidine and Rubiklin.

The commonly used in English-speaking classification of minerals according to Dana assigns the microcline also in the class of silicates, there, however, in the department of " framework silicates with Al- Si lattice ", where he, along with anorthoclase, celsian, Filatovit, Hyalophane, orthoclase Rubiklin and sanidine forms the group of " K (Na, Ba) - feldspars ."

Varieties and modifications

The compound K [ AlSi3O8 ] is dimorphic, meaning it occurs next to the triclinic microcline on as crystallizing monoclinic orthoclase.

The only known variety is the light to dark green amazonite.

Education and Locations

Microcline forms magmatic in granite, pegmatite and syenite or metamorphic in different rocks. In addition, it forms Metamorphoses on sanidine.

Worldwide, microcline so far (as of 2010) are detected in over 3100 localities, so include Afghanistan, Egypt, Antarctica, Argentina, Armenia, Ethiopia, Australia, Belgium, Bolivia, Brazil, Burundi, Chile, China, Germany, Ecuador, Ivory Coast, Finland, France, French Guiana, Greece, Greenland, Guinea, Guyana, Iceland, India, Israel, Italy, Japan, Cameroon, Canada, Kazakhstan, Kenya, Kyrgyzstan, Democratic Republic of the Congo, North and South Korea, Madagascar, Malawi, Morocco, Macedonia, Mexico, Mongolia, Mozambique, Myanmar, Namibia, New Zealand, Niger, Norway, Austria, Pakistan, Paraguay, Poland, Portugal, Romania, Russia, Zambia, Saudi Arabia, Sweden, Switzerland, Zimbabwe, Slovakia, Somalia, Somaliland, Spain, Sri Lanka, South Africa, Swaziland, Tajikistan, Tanzania, Thailand, Uganda, Ukraine, Uzbekistan, the United Kingdom, the United States (U.S.), Vietnam and Belarus.

The largest ever found microcline single crystal was discovered in 1981 in the Devils Hole Beryl Mine in Fremont County, Colorado, in the United States. The crystal is 49.38 meters in length, has a cross section of 35,97 m · 13.72 meters and a weight of 15,908.89 metric tons.

Crystal structure

Microcline crystallized in the triclinic space group C1 with the lattice parameters a = 8.59 Å; b = 12.97 Å; c = 7.22 Å; α = 90.6 °; β = 116.0 ° and γ = 87.6 °, and four formula units per unit cell.

Use

Microcline used as a raw material in the ceramic, glass and enamel industry. His variety Amazonite is used as a gemstone use.