Chemistry:Buddingtonite
| Buddingtonite | |
|---|---|
| General | |
| Category | Silicate mineral |
| Formula (repeating unit) | NH4AlSi3O8 |
| Strunz classification | 9.FA.30 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2) or sphenoidal (2/m) |
| Space group | C2/m (no. 12) |
| Unit cell | a = 8.57 Å, b = 13.03 Å, c = 7.18 Å; β = 112.73°; Z = 4 |
| Identification | |
| Color | Colorless |
| Crystal habit | Compact masses replacing plagioclase as pseudomorphs |
| Cleavage | Good on {001}, distinct on {010} |
| Tenacity | Brittle |
| Mohs scale hardness | 5.5 |
| |re|er}} | Vitreous |
| Streak | Light grey to yellow (impure specimens) |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 2.32 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.530 nβ = 1.531 nγ = 1.534 |
| Birefringence | δ = 0.004 |
| 2V angle | Calculated: 60° |
| References | [1][2][3][4] |
Buddingtonite is an ammonium feldspar with formula: NH4AlSi3O8 (note: some sources add 0.5H2O to the formula). It forms by hydrothermal alteration of primary feldspar minerals. It is an indicator of possible gold and silver deposits, as they can become concentrated by hydrothermal processes. It crystallizes in the monoclinic crystal system and is colorless to white with a vitreous luster. Its structure is analogous to that of high sanidine (KAlSi3O8). Buddingtonite has a hardness of 5.5 and a specific gravity of 2.32.
Buddingtonite was discovered in 1964 at the Sulfur Bank mine near Clear Lake in Lake County, California.[6] Clear Lake is at the north end of The Geysers geothermal area. It also occurs in the Tonopah, Nevada[7] area and in hydrothermal areas in New Zealand[8] and Japan . It has also been reported from the sedimentary Phosphoria Formation in Idaho,[9] South Dakota,[10] Wyoming, and Montana. It occurs in the oil shale deposit, near Proserpine, Queensland, Australia .[11]
It was named for Arthur Francis Buddington (1890–1980), a petrologist at Princeton University.
References
- ↑ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Buddingtonite". Mineral Data Publishing. http://www.handbookofmineralogy.org/pdfs/buddingtonite.pdf.
- ↑ Buddingtonite, MinDat.org, http://www.mindat.org/show.php?id=796
- ↑ Webmineral data
- ↑ Mookherjee, M.; Redfern, S. A. T.; Swainson, I.; Harlov, D. E. (December 2004). "Low-temperature behaviour of ammonium ion in buddingtonite [N(D/H)4AlSi3O8] from neutron powder diffraction". Physics and Chemistry of Minerals 31 (9): 643–649. doi:10.1007/s00269-004-0425-8. Bibcode: 2004PCM....31..643M.
- ↑ 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.
- ↑ "Buddingtonite, an ammonium feldspar with zeolitic water". American Mineralogist 49 (7–8): 831–50. 1964.
- ↑ "Quantitative reflectance spectroscopy of buddingtonite from the Cuprite mining district, Nevada". Journal of Geophysical Research 99 (B2): 2887–95. 1994. doi:10.1029/93JB02975. Bibcode: 1994JGR....99.2887F.
- ↑ "Characterizing the hydrothermal alteration of the Broadlands-Ohaaki geothermal system, New Zealand, using short-wave infrared spectroscopy". Journal of Volcanology and Geothermal Research 106 (1–2): 53–65. 2001. doi:10.1016/S0377-0273(00)00264-X. Bibcode: 2001JVGR..106...53Y.
- ↑ Gulbrandsen RA (1974). "Buddingtonite, ammonium feldspar, in the Phosphoria Formation, southeastern Idaho". USGS Journal of Research 2 (6): 693–7.
- ↑ "NH4+ in pegmatitic feldspars from the southern Black Hills, South Dakota". American Mineralogist 73: 818–21. 1988.
- ↑ "Buddingtonite (NH4-feldspar) in the Condor Oilshale Deposit, Queensland, Australia". Mineralogical Magazine 47 (344): 327–34. 1983. doi:10.1180/minmag.1983.047.344.07. Bibcode: 1983MinM...47..327L.
Other reading
- "Holotype buddingtonite, an ammonium feldspar without zeolitic H2O". American Mineralogist 78: 204–209. 1993. https://pubs.geoscienceworld.org/msa/ammin/article-abstract/78/1-2/204/105213/Holotype-buddingtonite-An-ammonium-feldspar. Retrieved 13 June 2022.
- "Hydrothermally grown buddingtonite, an anhydrous ammonium feldspar (NH4AlSi3O8)". Physics and Chemistry of Minerals 15 (4): 323–328. 1988. doi:10.1007/BF00311036. Bibcode: 1988PCM....15..323V.
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