Whewellite
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| Whewellite | |
|---|---|
| Lua error in package.lua at line 80: module 'Module:InfoboxImage/data' not found. A white Whewellite crystal from Schlema, Germany | |
| General | |
| Category | Oxalate minerals |
| Formula | CaC2O4·H2O |
| IMA symbol | Whe[1] |
| Strunz classification | 10.AB.45 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/c (no. 14) |
| Identification | |
| Color | Colorless, yellowish, brownish |
| Crystal habit | Equant or stout prismatic crystals |
| Twinning | e {101} twin plane |
| Cleavage | {101} good, {010} imperfect, {001} indistinct, {110} indistinct |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 2.5–3 |
| Luster | Vitreous to pearly |
| Diaphaneity | Transparent |
| Specific gravity | 2.23 |
| Optical properties | Biaxial (+), colorless (transmitted light) |
| Solubility | Insoluble in water, soluble in acids |
| References | [2][3][4][5] |
Whewellite /ˈhjuːəlaɪt/ is a mineral, hydrated calcium oxalate, formula Ca C2O4·H2O.[6] Because of its organic content it is thought to have an indirect biological origin; this hypothesis is supported by its presence in coal and sedimentary nodules. However, it has also been found in hydrothermal deposits where a biological source appears improbable. For this reason, it may be classed as a true mineral.
Whewellite, or at least crystalline calcium oxalate, does also arise from biological sources. Small crystals or flakes of it are sometimes found on the surfaces of some cacti, and kidney stones frequently have the same composition.
Whewellite was named after William Whewell (1794–1866), an English polymath, naturalist and scientist, professor of moral philosophy at Cambridge and inventor of the system of crystallographic indexing.[2]
Heat decomposition
Whewellite is used as a thermogravimetric analysis standard due to its well-known decomposition temperatures and products.
See also
- Kidney stones
- List of minerals recognized by the International Mineralogical Association
- List of minerals named after people
References
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- ^ Page Module:Citation/CS1/styles.css has no content.Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b Whewellite: mindat.org
- ^ Webmineral.com
- ^ Page Module:Citation/CS1/styles.css has no content."Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2016-03-03. Retrieved 2011-05-15.
- ^ Page Module:Citation/CS1/styles.css has no content.Tazzoli, V.; Domeneghetti, M.C. (1980). "The crystal structures of whewellite and weddellite: re-examination and comparison". American Mineralogist. 65: 327–334. Retrieved 31 December 2020.
- ^ Page Module:Citation/CS1/styles.css has no content."whewellite". Merriam-Webster Dictionary. Retrieved 30 May 2024.
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Bibliography
- Palache, P.; Berman H.; Frondel, C. (1960). "Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)" John Wiley and Sons, Inc., New York, pp. 1099–1101.
