ගිනිබොකු තෝර
| ගිනිබොකු තෝර | |
|---|---|
 Andalusite | |
| General | |
| Category | Nesosilicates |
| රසායනික සූත්රය | Al2SiO5 |
| Strunz classification | 09.AF.10 |
| Crystal symmetry | 2/m 2/m 2/m - Dipyramidal |
| Unit cell | a = 7.7980 Å b = 7.9031 Å c = 5.5566 Å; Z = 4 |
| Identification | |
| පාට / පැහැය | Pink, violet, yellow, green, white, gray; in thin section, colorless to pink or green |
| Crystal habit | As euhedral crystals or columnar aggregates having nearly square cross sections; fibrous compact to massive |
| Crystal system | orthorhombic |
| Twinning | On {101}, rare |
| Cleavage | Good on {110}, poor on {100} |
| Fracture | uneven to subconchoidal |
| Mohs scale hardness | 6.5 - 7.5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent to nearly opaque with inclusions |
| Specific gravity | 3.17 (+/- .04) |
| Optical properties | double refractive, biaxial negative; chiastolite has anomalous aggregate reaction.[1] |
| Refractive index | nα = 1.629 - 1.640 nβ = 1.633 - 1.644 nγ = 1.638 - 1.650 |
| Birefringence | δ = 0.009 - 0.010 |
| Pleochroism | Weak |
| 2V angle | 71 - 86° |
| Dispersion | r < v strong |
| Ultraviolet fluorescence | non-fluorescent |
| References | [1][2][3][4] |
- ^ a b Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
- ^ http://rruff.geo.arizona.edu/doclib/hom/andalusite.pdf Handbook of Mineralogy
- ^ http://www.mindat.org/show.php?id=217&ld=1&pho= Mindat.org
- ^ http://webmineral.com/data/Andalusite.shtml Webmineral data