Amazonite

Amazonite
General and classification
chemical formula	K [AlSi 3 O 8 ]
Mineral class; (and possibly department)	Framework silicates (tectosilicates)
System no. to Strunz ; and to Dana	see microcline; see microcline
Similar minerals	Turquoise , jade
Crystallographic Data
Crystal system	triclinic
Crystal class ; symbol	triclinic-pinacoidal 1
Twinning	lamellar according to albite law and periclinic law
Physical Properties
Mohs hardness	6 to 6.5
Density (g / cm 3 )	2.56 to 2.58
Cleavage	good to perfect
Break ; Tenacity	uneven to scalloped
colour	green, bluish green
Line color	White
transparency	translucent
shine	Glass gloss, pearlescent
Crystal optics
Refractive index	n = 1.522 to 1.530
Birefringence	δ = 0.008
Optical character	biaxial negative
Pleochroism	is missing
Other properties
Chemical behavior	soluble in hydrofluoric acid

Amazonite , also called Amazon stone , is a light to dark green mineral variety of Mikroklin from the mineral class of silicates , more precisely a framework silicate from the group of feldspars . It crystallizes in the triclinic crystal system and its chemical formula corresponds to that of the microcline (K [AlSi ₃ O ₈ ]) with a small amount of lead , which is also responsible for the color. Together with the feldspars, the amazonite is one of the most abundant minerals on earth.

Amazonite is only processed into gemstones . One exception is the Amazonite granite called "Monsun", which occurs in Chittor in India and is used in exclusive interior fittings.

Etymology and history

Amazonite was already used to make jewelry in ancient Egypt . Scientists later derived the name from the Amazon River , where it has not yet been found.

In contrast, Alexander von Humboldt (1769-1859) reported on an Indian tribe who lived on the Rio Negro and wore amulets made of amazonite. These should supposedly come from a country where women lived without men ( Amazons ).

Varieties

Since microcline forms a mixed series together with orthoclase , sanidine and albite as the end member, it has now been switched to assigning amazonite to all blue to green, lead-containing varieties of the minerals in question. Amazonite must therefore be viewed as a collective name for the varieties microcline amazonite , orthoclase amazonite , albite amazonite and the various plagioclase amazonites .

Education and Locations

Amazonite with smoky quartz

Amazonite forms magmatic in granite , syenite and pegmatite .

Find places are for example in Crystal Peak, Colorado in the USA , Brazil , India , Madagascar and Norway .

Use as a gem stone

Amazonite in different table cuts

For pieces of jewelery, amazonite is usually given the so-called table cut or cabochon cut, but it is also used in spherical form to make necklaces and craft items (e.g. sculptures ). Because of its structure-related good cleavage properties , however, it is very pressure-sensitive and difficult to enclose.

literature

Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 264 ( Dörfler Natur ).
Walter Schumann: Precious stones and gemstones. All species and varieties in the world. 1600 unique pieces . 13th revised and expanded edition. BLV Verlags-GmbH., Munich et al. 2002, ISBN 3-405-16332-3 , p. 180 .

Web links

Commons : Amazonit - collection of images, videos and audio files

Wiktionary: Amazonite - explanations of meanings, word origins, synonyms, translations

Individual evidence

↑ What is the most common mineral on earth? Retrieved April 25, 2017 .

[1] What is the most common mineral on earth? Retrieved April 25, 2017 .