Amblygonite

Amblygonite is a rarely occurring mineral from the mineral class of anhydrous phosphates with foreign anions. It crystallizes in the triclinic crystal system with the chemical composition (Li, Na) Al [( F, OH ) | PO4 ] and usually develops short prismatic crystals, but also granular to massive aggregates that knows either colorless or by foreign admixtures, gray, pink, may be yellowish, greenish or bluish colored.

Special Features

Amblygonite is in its optical properties of quartz and albite very similar and is therefore often confused with them. Through a flame test for lithium ( you hold a sample in a gas flame you see a bright red flame), its density and its unusual cleavage can distinguish it from the others.

Etymology and history

The name Amblygonite is a composition de Greek words άμβλύς ( amblys ) for " blunt" and γόνυ ( goni ) for " angle" and refers to the fact that amblygonite in different directions, each with different angles, but different from 90 °, splits.

First described it in 1817 by August Breithaupt.

Classification

In the old classification of minerals according to Strunz ( 8th edition ) of the Amblygonite is part of the Department of " anhydrous phosphates with foreign anions ", where it forms with Griphit, Montebrasite, Natromontebrasit, Tancoit and Tavorit a group. Since the new classification of minerals according to Strunz ( 9th edition ), however, this division is precisely divided by the size of the cations and the mineral is now with Montebrasite and Tavorit in the subdivision of " anhydrous phosphates with foreign anions and only medium-sized cations, (OH, etc.): RO 4 to find " less than" 1:1 ".

The classification of minerals according to Dana assigns the amblygonite also in the department of " anhydrous phosphates ", There but in the subdivision " with hydroxyl (groups) or halogen ( s) with the composition ( AB) 2 ( XO4 ) Zq ".

Education and Locations

Amblygonite is likely to form in igneous rocks and is, therefore, together with spodumene, lepidolite or Zinnwaldite or in phosphate pegmatites mainly found in lithium pegmatites along with apatite, monazite and Triphylin. Rarely arises Amblygonite from hydrothermal solutions in the aged or vein deposits.

Locations include Laghman in Afghanistan; Córdoba in Argentina; New South Wales and Western Australia in Australia; Minas Gerais and São Paulo in Brazil; Henan and Jiangxi in the People's Republic of China; Chemnitz and Ehrenfriedersdorf in Germany; Viitaniemi in Finland; Manitoba and Nova Scotia in Canada; Sud- Kivu in the Democratic Republic of Congo; Mogok in Myanmar; Uto in Sweden; Bohemia, Moravia and Vernéřov in the Czech Republic; and Black Hills / South Dakota in the United States. Huge, massive aggregates of up to 200 tons were also ( also in South Dakota) discovered in Keystone.

Crystal structure

Crystallizes in the triclinic crystal system amblygonite in the space group P1 with the lattice parameters a = 6.64 Å, b = 7.74 Å and c = 6.91 Å; α = 90.35 °, β = 117.33 ° and γ = 91.01 ° and four formula units per unit cell and is isotypic to Tavorit, ie these two minerals have the same crystal structure.

Use

As a raw material

Amblygonite An important ore for the recovery of lithium, but is also used as a raw material in the ceramic industry.

As a gemstone

Amblygonite is one of the lesser-known gems. Can see confusingly similar to polished Clear varieties in facet shape but the more valuable " gems " golden beryl, citrine and others. More confusion opportunities exist with apatite, brazilianite and the green to yellowish green Spodumenvarietät Hiddenite.