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Nantokite from
Dyke Park, Stamford, Fairfield County, Connecticut, USA
| Locality type: | Park | |
| Classification | ||
|---|---|---|
| Species: | Nantokite | |
| Formula: | CuCl | |
| Comments: | Henderson (1967) reports: colorless translucent to white opaque 0.5 mm tetrahedra with and on cuprite and atacamite. Some of the crystals showed triangular etch pits on the tetrahedron faces (Fig. 1) and many were skeletal (Fig. 2) or occurred in parallel growth. Identification was made as follows. Very few white tetrahedral minerals are known, and of these, only nantokite CuCl and marshite CuI were likely to form from copper in the presence of sea water. Both these minerals are optically isotropic, and the above material was found to be so. In addition, the index of refraction was found to be about 1.93. Nantokite has an index of 1.930 while marshite has an index of 2.346. As a matter of fact, the index of refraction is alone sufficient to identify this mineral as nantokite since only a handful of minerals have indices as high as 1.9, and the above are the only tetrahedral minerals in the group. Many of the nantokite crystals were altered in part or entirely to a lime green mineral, and a few to a sulfur yellow material. It is interesting to note that nantokite has been reported to alter in air to the green mineral paratacamite. | |
| Habit: | micro tetrahedra, etched to skeletal or in parallel groups | |
| Colour: | colorless to white | |
| Abundance at site: | Very Rare | |
| Confirmation | ||
| Validity: | Believed Valid | |
| Data | ||
| Mineral Data: | Click here to view Nantokite data | |
| Locality Data: | Click here to view Dyke Park, Stamford, Fairfield County, Connecticut, USA | |
| Data Identifiers | ||
| Mindat Occurrence Record ID: | 850430 | |
| Long-form Identifier: | 1:3:850430:2 | |
| GUID (UUID V4): | 0 | |
| References | ||
