Pulo di Molfetta caves, Apulia, Italy
Speleothems: crystals in small pockets inside the niter speleothems
Frequency: Rare
Other occurrence: cotton-like tufts on the floor (a small cave in Apulia) fibrous flowers 1-3 cm long (Ludwig Cave, Namibia) eflorescent cotton mats (Kartcher Caverns, Arizona, USA)
First description of cave occurrence: Zimmermann, G. 1788. Voyage à la nitrière naturelle qui se trouve à Molfetta dans la terre de Bari en Apulia. Venezia, Storti, 44p Forti, P. & Palmisano, G. 1989. I nitrati del Pulo di Molfetta: mineralogia e meccanismi genetici. Atti 15 Congrezo Nazionale di Speleologia (Castelanna 1987): 229-250
First description of non-cave occurrence: Shepard, C.U. 1835. Nitrocalcite. Calcareous earthy-salt. in Treatise on Mineralogy: Second Part, Volume II Hezekiah Howe & Co. New Haven: 84-85
Other cave locations & References: David's and Chaos Caves, South Africa: Martini, J.E. & Kavalieris, I. 1978. Mineralogy of the Transvaal caves. Transactions of the Geological Society of South Africa 81: 47-54 a small cave in Apulia, Italy: Forti. P. 1983. I minerali di grota. Speleo 9: 9-24 Ludwig Cave, Namibia: Martini, J. (pers. comm in Hill, C. & Forti, P. 1997. Cave Minerals of the World (2nd ed.). National Speleological Society, Huntsville AL, 464p) Kartchner Caverns, AZ, USA: Hill, C.A. & Buecher, R.H. 1991. Nitrocalcite in Kartchner Caverns, Kartchner Caverns State Park, Arizona. Cave Research Foundation, Annual Report 32: 34-35
Group: Nitrates
Chemical formula: Ca(NO3)2·4H2O
[According to the official IMA-CNMNC List of Mineral Names (http://nrmima.nrm.se/imalist.htm)]
Deposition and stability: The limestone is the source of calcium, while the source of nitrate is usually the bat guano (or in exceptional cases - an olive orchad above the cave (through capilarity), e.g. Pulo di Molfetta, Italy; a sheep corral in the cave, e.g. a small cave in Apulia, Italy) Very soluble in water. At high humidity it deliquesces and dissapears
Color: colorless to milky-white
Luster: silky to transparent
Diagnostic features: It has a strong, bitter-cool taste
Associated sometimes with niter and nitromagnesite
- Monoclinic