Geikielite
Geikielite is a magnesium titanium oxide mineral with formula: MgTiO3. It is a member of the ilmenite group. It crystallizes in the trigonal system forming typically opaque, black to reddish black crystals.
| Geikielite | |
|---|---|
 Crystals of geikielite from the Maxwell quarry, Chelsea, Outaouais, Québec, Canada | |
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | MgTiO3 |
| Strunz classification | 4.CB.05 |
| Crystal system | Trigonal |
| Crystal class | Rhombohedral (3) (same H-M symbol) |
| Space group | R3 |
| Unit cell | a = 5.05478(26) Å c = 13.8992(7) Å; Z = 6 |
| Identification | |
| Color | Black, ruby red uncommon; red internal reflections |
| Crystal habit | Tabular prismatic crystals, also as finely granular masses |
| Cleavage | Good on {1011} |
| Mohs scale hardness | 5 - 6 |
| Luster | Sub-metallic |
| Streak | Purplish brown |
| Diaphaneity | Opaque to translucent |
| Specific gravity | 3.79 - 4.2 |
| Optical properties | Uniaxial (-) |
| Refractive index | nω = 2.310 - 2.350 nε = 1.950 - 1.980 |
| Birefringence | δ = 0.360 - 0.370 |
| Pleochroism | Weak, O = pinkish red, E = brownish to purplish red |
| References | [1][2][3] |
It was first described in 1892[4] for an occurrence in the Ceylonese gem bearing gravel placers. It was named for Scottish geologist Sir Archibald Geikie (1835–1924).[3] It occurs in metamorphosed impure magnesian limestones, in serpentinite derived from ultramafic rocks, in kimberlites and carbonatites. Associated minerals include rutile, spinel, clinohumite, perovskite, diopside, serpentine, forsterite, brucite, hydrotalcite, chlorite and calcite.[1]
References
- Handbook of Mineralogy
- Geikielite on Mindat.org
- Geikielite on Webmineral
- Fletcher, L. (1892). "Geikielite and Baddeleyite, Two New Mineral Species". Nature. 46 (1200): 620–621. Bibcode:1892Natur..46..620F. doi:10.1038/046620b0.
Further reading
- Ghiorso, Mark S. (1990). "Thermodynamic properties of hematite — Ilmenite — Geikielite solid solutions". Contributions to Mineralogy and Petrology. 104 (6): 645–667. Bibcode:1990CoMP..104..645G. doi:10.1007/BF01167285.
- Reynard, B.; Guyot, F. (1994). "High-temperature properties of geikielite (MgTiO3-ilmenite) from high-temperature high-pressure Raman spectroscopy ? Some implications for MgSiO3-ilmenite". Physics and Chemistry of Minerals. 21 (7): 441. Bibcode:1994PCM....21..441R. doi:10.1007/BF00202274.
- Baura-Peña, M. P.; Martínez-Lope, M. J.; García-Clavel, M. E. (1991). "Synthesis of the mineral geikielite MgTiO3". Journal of Materials Science. 26 (16): 4341. Bibcode:1991JMatS..26.4341B. doi:10.1007/BF00543648.
- Robie, Richard A.; Haselton, H.T.; Hemingway, Bruce S. (1989). "Heat capacities and entropies at 298.15 K of MgTiO3(geikielite), ZnO (zincite), and ZnCO3 (smithsonite)". The Journal of Chemical Thermodynamics. 21 (7): 743. doi:10.1016/0021-9614(89)90058-X.
- Gieré, Reto (1987). "Titanian clinohumite and geikielite in marbles from the Bergell contact aureole". Contributions to Mineralogy and Petrology. 96 (4): 496–502. Bibcode:1987CoMP...96..496G. doi:10.1007/BF01166694.
- Parthasarathy, G. (2007). "Electrical resistivity of nano-crystalline and natural MgTiO3−geikielite at high-pressures up to 8 GPa". Materials Letters. 61 (21): 4329–4331. doi:10.1016/j.matlet.2007.01.097.
- Mitchell, Jeremy N.; Yu, Ning; Sickafus, Kurt E.; Nastasi, Michael A.; McClellan, Kenneth J. (1998). "Ion irradiation damage in geikielite (MgTiO3)". Philosophical Magazine A. 78 (3): 713. doi:10.1080/01418619808241931.
- Chao, G. Y.; Hounslow, A. W. (June 1967). "Geikielite; a new Canadian occurrence". The Canadian Mineralogist. 9 (1): 95–100.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.