Skipton (lavatube) Cave, Victoria, Australia
Speleothems: loose tabular crystals with remnants of struvite in them white, opac, compact powder after struvite
Frequency: Rare
Other geologic settings: -
Other occurrence: white crystalline coatings or crusts (Ficus, Boon and Crystal Caves, Transvaal, South Africa) rose colored crust and thick flowstone (Gumburdek Cave, Bulgaria) white wall popcorn (Gâuab Aas Cave, Namibia) or crust (Gcwihaba Cave, Namibia) small hard nodules consisting of platy transparent crystals (Niah caves, Sarawak, Malaysia)
First description of cave occurrence: vom Rath, G. 1879. Note sur deux nouveaux phosphates du guano. Bulletin de la Société Minéralogique de France 2: 79-82
First description of non-cave occurrence: -
Other cave locations & References: Petrogale Cave, Western Australia Ficus, Boon and Crystal Caves, Transvaal, South Africa Gumburdek Cave, Bulgaria - Kolev, B & Shopov, Y.Y. 1992. The volcanic caves in Bulgaria. Geo2 (Geol. Geog. Sect., Natl. Speleol. Soc.) 19 (1): 22 Sul-Unkur cave, Khaidarkan, Kirghistan - Stepanov, V.I. 1971. Studies on the Khaidarkan caves, both hydrothermal and cold: in Velikii, A.S. et al. (eds.) Structural features and genetic sequences for some central Asian Hg-Sb depositions, Unpub. report, IMGRE All-Russian Geol. Found.: 184-220 (in Russian) Gâuab Aas and Gcwihaba caves, Namibia - Martini, J.E. 1996. Contribution to the mineralogy of the caves of Gcwihaba Hills, northwestern Botswana. South African Speleol. Assoc. Bull. 36 Niah caves, Sarawak, Malaysia - Wilford, G.E. 1965. The geology of Sarawak and Sabah caves. Bull. Geol. Surv. Borneo, Malaysia 6: 1-181
Longitude: 143°20'52''E
Water: No
Type of rock: basalt
Group: Phosphates
Chemical formula: Mg(PO3OH) · 3H2O
[According to the official IMA-CNMNC List of Mineral Names (http://nrmima.nrm.se/imalist.htm)]
Deposition and stability: it derived from guano and basalt (which provided magnesium) (in Skipton Cave) ussually it forms directly from guano solutions (in Niah caves, Malaysia) less often, it is a decomposition product of struvite, due to the loss of ammonia
Luster: dull
Hardness: 3
P205 40.73; Fe203 0.85; Mn203 0.21; MgO 22.37; H20 35.84 (H20 - by diference)
Mineral assemblage: + hannayite, struvite (Skipton Cave, Australia) + biphosphammite (Petrogale Cave, Western Australia) + taranakite (Sul-Unkur Cave, Kirghiztan) + gypsum (Gcwihaba Cave, Namibia) + variscite, vivianite, brushite (Niah caves, Malaysia)
- Orthorhombic
Cell parameter b (Å): 10.6781
Cell parameter c (Å): 10.0096
Cell parameter α (Å): 90
Cell parameter β (Å): 90
Cell parameter γ (Å): 90