Geikielite Explained
| Geikielite |
| Category: | Oxide mineral |
| Formula: | MgTiO3 |
| Imasymbol: | Gk[1] |
| Strunz: | 4.CB.05 |
| System: | Trigonal |
| Class: | Rhombohedral
(same H-M symbol) |
| Symmetry: | R |
| Unit Cell: | a = 5.05478(26) Å
c = 13.8992(7) Å; Z = 6 |
| Color: | Black, ruby red uncommon; red internal reflections |
| Habit: | Tabular prismatic crystals, also as finely granular masses |
| Cleavage: | Good on |
| Mohs: | 5 - 6 |
| Luster: | Sub-metallic |
| Streak: | Purplish brown |
| Diaphaneity: | Opaque to translucent |
| Gravity: | 3.79 - 4.2 |
| Opticalprop: | Uniaxial (-) |
| Refractive: | 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: | [2] [3] [4] |
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.
It was first described in 1892[5] for an occurrence in the Ceylonese gem bearing gravel placers. It was named for Scottish geologist Sir Archibald Geikie (1835–1924).[4] 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.[2]
Further reading
- 10.1007/BF01167285 . Thermodynamic properties of hematite — Ilmenite — Geikielite solid solutions . 1990 . Ghiorso . Mark S. . Mark S. Ghiorso . Contributions to Mineralogy and Petrology . 104 . 6 . 645–667. 1990CoMP..104..645G . 98522254 .
- 10.1007/BF00202274 . High-temperature properties of geikielite (MgTiO3-ilmenite) from high-temperature high-pressure Raman spectroscopy ? Some implications for MgSiO3-ilmenite . 1994 . Reynard . B. . Guyot . F. . Physics and Chemistry of Minerals . 21 . 7. 441 . 1994PCM....21..441R . 96095190 .
- 10.1007/BF00543648 . Synthesis of the mineral geikielite MgTiO3 . 1991 . Baura-Peña . M. P. . Martínez-Lope . M. J. . García-Clavel . M. E. . Journal of Materials Science . 26 . 16 . 4341. 1991JMatS..26.4341B . 94170430 .
- 10.1016/0021-9614(89)90058-X . Heat capacities and entropies at 298.15 K of MgTiO3(geikielite), ZnO (zincite), and ZnCO3 (smithsonite) . 1989 . Robie . Richard A. . Haselton . H.T. . Hemingway . Bruce S. . The Journal of Chemical Thermodynamics . 21 . 7 . 743.
- 10.1007/BF01166694 . Titanian clinohumite and geikielite in marbles from the Bergell contact aureole . 1987 . Gieré . Reto . Contributions to Mineralogy and Petrology . 96 . 4 . 496–502. 1987CoMP...96..496G . 86861792 .
- 10.1016/j.matlet.2007.01.097 . Electrical resistivity of nano-crystalline and natural MgTiO3−geikielite at high-pressures up to 8 GPa . 2007 . Parthasarathy . G. . Materials Letters . 61 . 21 . 4329–4331.
- 10.1080/01418619808241931 . Ion irradiation damage in geikielite (MgTiO3) . 1998 . Mitchell . Jeremy N. . Yu . Ning . Sickafus . Kurt E. . Nastasi . Michael A. . McClellan . Kenneth J. . Philosophical Magazine A . 78 . 3 . 713. 1998PMagA..78..713M .
- Geikielite; a new Canadian occurrence. The Canadian Mineralogist. 9. 1. 95–100. June 1967. Chao. G. Y.. Hounslow. A. W..
Notes and References
- Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
- http://rruff.geo.arizona.edu/doclib/hom/geikielite.pdf Handbook of Mineralogy
- http://www.mindat.org/min-1670.html Geikielite on Mindat.org
- http://www.webmineral.com/data/Geikielite.shtml Geikielite on Webmineral
- 10.1038/046620b0 . Geikielite and Baddeleyite, Two New Mineral Species . 1892 . Fletcher . L. . Nature . 46 . 1200 . 620–621. 1892Natur..46..620F . free .
