Stone, minerals and semiprecious of the world stone
Feldspar (silicates): Microcline -->rus
Diagnostic cart.
On a photo - standard of microcline. Down: crystals of amazon-stone (dark blue-green variety of microcline) from the state of Colorado (USA).
K Al Si3 O8
Crystal structure triclinic
Hardness on the Mohs scale 6
Specific unit weight mass 2,53-2,56
Cleavage perfect absolute
Fracture, break padman, wrong, fragile frail brittle
Colors light-grey, yellow, gold, light-red
Colors in powder triturate white
Glance (glitter, glare) glassy, mother-of-pear nacreous
Two large groups exude between feldspars: 1) potassium feldspars are a sanidine, Orthoclase with his variety adularia (Moon stone) and Microcline (him a green variety is an amazon-stone); 2) calcareous - natron sodium feldspars (so-called plagioclases).
Microcline is triclinic modification of aluminum silicate of potassium other representatives of which are a sanidine and Orthoclase. His crystals have the light-grey gray, grey, reddish and rather yellow colouring, very rarely green and, as compared to orthoclase, have more stand habitus.
Origin provenance genesis.
Microcline is a characteristic component of many rocks of granit and gneiss type.
Deposit minefield mine field occurrence subsoil.
As distinct rose crystals of Microcline, among many locations, be found in Kata-Francheze in Maddalene. The classic displays of microcline are disposed in the United States (USA) and Russia, on Ural.
Varieties.
An in-use on jeweller business variety is an amazon-stone - possesses the green or light-blue-green colouring. It rarely be found as massive aggregates, much more frequent - as the well-shaped crystals, having a short-prismatic type and well noticeable signs of planes of cleavage. Colouring, probably, is related to the special defects of crystalline grate, caused the presence of admixture of lead.
Got the name to down the river Amazon. Sensible to squeezing efforts. Most considerable deposit in the USA (state of Colorado), other in Brazil, India, on Madagascar, in Namibia, CIS (Ural, Kolskiy Kola Peninsula, Transbaikalia (Zabaykale), Pamir). Polished flat tables and cabochons. Jade reminds, turquoise.
Basic locations are disposed in Russia, North America, Brazil, India, on Madagascar and in Tanzania. Exposed to cutting in cabochon or ball for making of necklaces.
Microcline. Sonth Changa, Sitting down. Karelia, Russia. Height of crystal ~30 sm. A photo: © A.A. Evseev.
