Vote for your favorite mineral in #MinCup26! - Sphalerite vs. Anorthite
Both zinc ore Sphalerite and calcium plagioclase feldspar Anorthite have perfect cleavage that will split cleanly if you hit them with a hammer, but only one can claim a larger split of your votes!
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Opal from
Mont'Orfano (Montorfano), Mergozzo, Verbano-Cusio-Ossola Province, Piedmont, Italy


Locality type:Mountain
Classification
Species:Opal
Formula:SiO2 · nH2O
Confirmation
Validity:Believed Valid
Data
Mineral Data:Click here to view Opal data
Locality Data:Click here to view Mont'Orfano (Montorfano), Mergozzo, Verbano-Cusio-Ossola Province, Piedmont, Italy
Data Identifiers
Mindat Occurrence Record ID:1013528
Long-form Identifier:1:3:1013528:0
GUID (UUID V4):0
Nearest other occurrences of Opal
3.3km (2.1 miles) ⓘSeula mine, Mount Camoscio, Oltrefiume, Baveno, Verbano-Cusio-Ossola Province, Piedmont, Italy
8.2km (5.1 miles) ⓘNibbio-Val Faera (Nibbio-Val Fredda) pegmatites, Nibbio, Mergozzo, Verbano-Cusio-Ossola Province, Piedmont, Italy
17.7km (11.0 miles) ⓘAlzo, Pella, Novara Province, Piedmont, Italy
21.3km (13.2 miles) ⓘRio Graia, Trontano, Verbano-Cusio-Ossola Province, Piedmont, Italy
21.6km (13.4 miles) ⓘGrignaschi Quarry, Cosasca, Trontano, Verbano-Cusio-Ossola Province, Piedmont, Italy
22.5km (14.0 miles) ⓘEglio, Craveggia, Verbano-Cusio-Ossola Province, Piedmont, Italy
23.3km (14.5 miles) ⓘPiano del Lavonchio (Piano dei Lavonchi), Rio Vasca, Craveggia, Verbano-Cusio-Ossola Province, Piedmont, Italy
23.9km (14.8 miles) ⓘI Mondei (Ca' Mondei), Montescheno, Verbano-Cusio-Ossola Province, Piedmont, Italy
31.2km (19.4 miles) ⓘRencio quarries, Crodo gneiss quarries, Crodo, Verbano-Cusio-Ossola Province, Piedmont, Italy
32.3km (20.1 miles) ⓘPuricelli Quarry, Cavagnano, Cuasso al Monte, Varese Province, Lombardy, Italy
References
Roggiani A.G. (1969): Opale jalite e scheelite nel granito bianco del Montorfano. Rend. Soc. Ital. Mineral. Petr., 25, 2, 549-552
Boscardin M. (1972): Informazioni di mineralogia italiana. 21) Opale jalite e scheelite del Montorfano. Notizie Gruppo Mineral. Lombardo, 3, 1 (marzo 1972), 8
De Michele, V. (1974) Guida mineralogica d'Italia. Istituto Geografico De Agostini.
 
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