Pronunciation Guide 
General Information |
|
 Chemical Formula: |
Na4K3(Fe++,Mn++,Ti)2Si8O20(OH)4·4(H2O) |
| Environment: |
In hyperagpaitic pegmatites. |
| IMA Status: |
Approved IMA |
| Locality: |
Mt. Koashva, SE part of the Khibina alkaline massif, Kola Peninsula, Russia. |
| Name Origin: |
Named after Prof. Vadim Viktorovich Ershov (1939-1989) of the Moscow Mining Institute. |
| Synonym: |
IMA91.014 |
Classification |
|
| Dana Class: |
66.1.5.1 (66)Inosilicate Double-Width Unbranched Chains, W=2 |
| (66.1)with P=2 amphible type chains | |
| (66.1.5)Dana Group | |
| Strunz Class: |
VIII/H.04-30 VIII - Silicates |
| VIII/H - Phyllosilicates (layered), Tetragonal or pseudotetragonal layered structures [Si4O10]4- and others | |
| VIII/H.04 - Fenaksite series | |
Crystallography |
|
| Axial Ratios: |
a:b:c =0.8591:1:0.4424 |
| Cell Dimensions: |
a = 10.244, b = 11.924, c = 5.276, Z = 1; alpha = 103.136ø, beta = 96.033ø, gamma = 91.033ø V = 624.02 |
| Crystal System: |
Triclinic - Pinacoidal H-M Symbol ( -1) Space Group: P1- |
| X Ray Diffraction: |
By Intensity(I/Io): 2.99(1) 11.58(1) 2.709(0.8) |
Physical Properties |
|
| Cleavage: |
[100] Perfect, [010] Perfect |
| Color: |
olive green, brownish green, or yellowish green. |
| Density: |
2.75 - 2.69, Average = 2.72 |
| Diaphaniety: |
Transparent |
| Habits: |
Anhedral Grains - Granular minerals without the expression of crystal shapes, Fibrous - Crystals made up of fibers., |
| Hardness: |
2.5-3 - Finger Nail-Calcite |
| Luminescence: |
Non-fluorescent. |
| Luster: |
Vitreous (Glassy) |
| Streak: |
white |
Optical Properties |
|
| Optical Data: |
Biaxial (+), a=1.569, b=1.574, g=1.59, bire=0.0210, 2V(Calc)=60, 2V(Meas)=58. Dispersion medium, r > v. |
| Pleochroism (x): |
light green or yellowish green. |
| Pleochroism (y): |
light green or yellowish green. |
| Pleochroism (z): |
dark olive green or dark olive green. |
Other Information |
|
| References: |
NAME( MinRec) PHYS. PROP.(37th List of New Min.,Min. Mag.,1996) OPTIC PROP.(MinRec) |
| See Also: |
Links to other data for Ershovite : 1 -Athena Mineralogy 2 - EUROmin Project 3 -MinDat.org Location Data 4 -MinMax 5 -WWW-MINCRYST 6 -École des Mines de Paris Search for Ershovite using: Visit our Advertisers for Ershovite : |
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