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Epistilbite
Chemical Formula	CaAl2Si6O16·5H2O
Species	Silicates
Crystal System	Monoclinic
Mohs Scale	4
Specific Gravity	2.22-2.28
Color	Colorless, white, pinkish, yellowish
Streak	white
Luster	Vitreous
Refractive Index	n = 1.502 n = 1.510 n = 1.512
Diaphaneity	Transparent, Translucent
Cleavage	PerfectPerfect on
Fracture	Irregular/Uneven
Crystal Habit：Crystals prismatic; spherulitic, sheaflike aggregates
Geological Setting：Cavities in basalts and gneisses

Epistilbite is a zeolite, for aqueous sodium and calcium aluminum silicate minerals. Belongs to the low temperature phase zeolite facies, according to Professor Luo Huanji ( Lo, 1978) estimation of the pressure and temperature were 1.5Kb, 220~290 ℃. Natural zeolite is many

Porous materials, by univalent and two divalent metal cation aluminum silicate composition and structure, there are quite a few holes and channels, so the metal cation selective adsorption effect, can carry out ion exchange, thus having molecular sieves characteristics, can be of different types of gas separation, such as argon, nitrogen, ammonia, of great industrial application value. Chemical composition: ( Ca, Na2 ) Al2Si6O16.5H2O

Physical property

1: monoclinic crystal system

2 color: colorless, white, orange, red

3 polymorphs : column, fibrous, radially, common twinning structure

4 hardness: 4~4.5

5: good cleavage cleavage

6: the proportion of 2.22~2.28

7: Glass luster luster

Occurrence

In the form of igneous cracks or holes, which belongs to the secondary mineral, often with other zeolite mineral, such as zeolite (Mordenite ), heulandite, Stilbite ( Heulandite ) ( Stilbite ), calcium ( Scolecite ), zeolite laumontite ( Laumontite ), chabazite (Chabazite ) etc.. Can also be formed in a mild metamorphic rocks, as the low temperature metamorphic degree index minerals ( Lan, 1982).

Use

In the industry are often used in wastewater treatment and gas adsorption, in agriculture is often used in soil improvement agent and feed additive, and can also be used in solar energy storage.

Optical properties of

Sheet is colorless and transparent, often radiating assembly. Low negative projection. Surface roughness is not significant, Duocheng columnar section. Orthogonal polarization interference color is a pale, it extended symbols. Because Np is nearly perpendicular to the ( 100), it has the shape of section extending parallel extinction can be seen on acute bisectrix interference figure. Dispersion strong.

Place of origin

Nearly a few found in Chi Mei Igneous Complex of.