Chemistry:Homilite
From HandWiki
Short description: Borosilicate mineral
| Homilite | |
|---|---|
| General | |
| Category | Nesosilicate |
| Formula (repeating unit) | Ca2(Fe2+,Mg)B2Si2O10 |
| Strunz classification | 8/B.29-30 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) |
| Space group | P21/b |
| Unit cell | a = 9.78 Å, b = 7.61 Å, c = 4.78 Å; β = 90.56°; Z = ? |
| Identification | |
| Color | Greenish to brownish black |
| Mohs scale hardness | 5–5 1⁄2 |
| |re|er}} | Vitreous, resinous |
| Diaphaneity | Opaque |
| Specific gravity | 3.34 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.715 nβ = 1.725 nγ = 1.738 |
| Birefringence | δ = |
| 2V angle | Measured: 80° |
| References | [1] [2] [3] |
Homilite is a borosilicate mineral belonging to the gadolinite group of minerals with formula Ca
2(Fe,Mg)B
2Si
2O
10.
It occurs as brown monoclinic crystals (space group P21/a[5]) within feldspar masses in pegmatite and was discovered in 1876 in Stoko island, Langesundfiord, Norway . The name is from the Greek for to occur together, in allusion to its association with meliphanite and allanite.
References
- ↑ Mineral Society of America Handbook (PDF)
- ↑ Mindat with locations
- ↑ Webmineral data
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ Miyawaki, R.; Nakai, I.; Nagashima, K. (15 January 1985). "Structure of homilite, Ca2.00(Fe0.90Mn0.03)B2.00Si2.00O9.86(OH)0.14". Acta Crystallographica Section C Crystal Structure Communications 41 (1): 13–15. doi:10.1107/S010827018500261X.
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