Stone, minerals and semiprecious of the world stone
Epidotes (silicates): Epidote (pistacite) -->rus
Diagnostic cart.
On a photo. Well-shaped crystals of Epidote.
Ca2 Al3O OH SiO4 Si2O7
Crystal structure monoclinic
Hardness on the Mohs scale 6-7
Specific unit weight mass 3,35-3,38
Cleavage perfect absolute
Fracture, break padman, wrong
Colors green
Colors in powder triturate grey
Glance (glitter, glare) glassy
Epidote, or pistacite, is a difficult silicate of calcium, aluminium and iron. Got the name from greek epidosos is an increase. In a section one side of prism of long other. A synonym is related to the pistachio color. To entangle Epidote easily with a vesuvianite.
Glassy off-gloss. Transparent, rarer transparent. Colors: pistachio-green (from here the second name), dark-green. A line is grey. Fracture, break padman, uneven, rough. Cleavage perfect absolute. Appears in skarn and at metamorphism, crystals - in drusy cavities and on cracks. Crystals (monoclinic Crystal structure) are extended, prismatic, needle, rich in verges, often form a group in bunches, dense radially-radiant aggregates. Twins are not uncommon. Places of distribution: Ore mountains (Germany, Czekh), Alps, in the CIS Ural and Alaska.
Klinozoisite is a littleferrous variety of Epidote of grey or light pink color. Pemontit is a manganiferous variety of Epidote of crimson color. Forms radiant aggregates.
Epidote is mentioned also under the name pistacite. Presented both prismatic crystals and silicular and fibred aggregates. Twins are characteristic. A mineral is painted in dark-green, pistachio -green, greenish-yellow, gold color; brilliance of glassy, cleavage of perfect absolute along bottom base.
Diagnostic indication.
Does not dissolve in acids, in flame of candle melt fuse easier, than klinozine Ruby.
Origin provenance genesis.
Originally it mineral mainly metamorphic rocks. It appears on the contact of limestones with slates, and also in cracks among femic rocks (amphibolites, gabbro and other). In addition, can be formed in the process of hydrothermal changes of calcium plagioclases.
Deposit minefield mine field occurrence subsoil.
The wonderful standards of Epidote in Italy are known from Val'-d'ala, Val'-de-Suza and Traverselly (a province is Turin), and also from Val'-malenko (province of Sondrio). Presently the best copies take a place from France, Switzerland, Norway, Brazil and different countries of North America. Almost all of standards, most interesting from the jeweller point of view, act from Knappenvalde (Austria).
Use, practical application, deployment.
Used on jeweller business. On Ural there is bottle-green transparent variety of Epidote - Pushkinite, which is exposed to cutting.
