Pronunciation Guide 
General Information |
|
 Chemical Formula: |
(K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] |
| IMA Status: |
Not IMA Approved |
| Synonym: |
Gumbelite |
| Hydromica | |
| Hydromuscovite | |
Classification |
|
| Dana Class: |
71.2.2d.2 (71) |
| (71.2)Dana Type | |
| (71.2.2d)Mica Group (Hydromica subgroup) | |
| Strunz Class: |
VIII/H.19-15 VIII - Silicates |
| VIII/H - Phyllosilicates (layered) Mica like with [Si4O10]4- and related groups | |
| VIII/H.19 - Brammallite ? - Yakhontovite series | |
Crystallography |
|
| Axial Ratios: |
a:b:c =0.5768:1:1.1492 |
| Cell Dimensions: |
a = 5.18, b = 8.98, c = 10.32, Z = 2; beta = 101.83ø V = 469.85 |
| Crystal System: |
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C2/m |
| X Ray Diffraction: |
By Intensity(I/Io): 4.43(1) 2.56(0.85) 3.66(0.4) |
Physical Properties |
|
| Cleavage: |
[???] Perfect |
| Color: |
white. |
| Density: |
2.6 - 2.9, Average = 2.75 |
| Diaphaniety: |
Translucent |
| Hardness: |
1-2 - Between Talc and Gypsum |
| Luster: |
Earthy (Dull) |
| Streak: |
white |
Optical Properties |
|
| Optical Data: |
Biaxial (-), a=1.535-1.57, b=1.555-1.6, g=1.565-1.605, bire=0.0300-0.0350, 2V(Calc)=42-68, 2V(Meas)=5-25. Dispersion none. |
| Pleochroism (x): |
colorless. |
| Pleochroism (y): |
colorless. |
| Pleochroism (z): |
colorless. |
Other Information |
|
| References: |
NAME( Dana8) PHYS. PROP.(Eur. J. Min.,Vol.9,p821-827,1997) OPTIC PROP.(Heinrich65) |
| See Also: |
Links to other databases for Illite : 1 -Athena Mineralogy 2 - EUROmin Project 3 - Franklin Minerals(Dunn) 4 -MinDat.org Location Data 5 -MinMax 6 - Minerals of Wisconsin 7 -École des Mines de Paris Search for Illite using: Visit our Advertisers for Illite : Ask about Illite here : |
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