 |
Chemical Formula | NiAs2 |
|
Composition | Nickel arsenide, sometimes with some cobalt and iron. If the nickel (Ni) is replaced by more than 50% iron (Fe), the mineral is not Rammelsbergite, but Loellingite, and if it is replaced by more than 50% cobalt (Co), the mineral is Safflorite. |
|
Variable Formula | (Ni,Fe,Co)As2 |
|
Color | Silver-white with a reddish tint. Tarnishes yellow or pink. |
|
Streak | Gray |
|
Hardness | 5½ - 6 |
|
Crystal Forms and Aggregates |
(Orthorhombic) Seldom occurs in crystals, which are tabular and short prismatic. Most commonly occurs massive, but also grainy, fibrous, and in coxcomb aggregates. |
|
Transparency | Opaque |
|
Specific Gravity | 6.9 - 7.1 |
|
Luster | Metallic |
|
Cleavage | None |
|
Fracture | Uneven |
|
Tenacity | Brittle |
|
In Group | Sulfides ; Arsenides |
|
All About | Rammelsbergite belongs to the Loellingite group, which is a group of chemically related isomorphous minerals. They are all rare minerals, and only a few of the more common ones are discussed in this guide. Other members discussed in this guide are Loellingite and Safflorite. |
|
Striking Features | Color and tarnish, crystal habits |
|
Popularity (1-4) | 4 |
|
Prevalence (1-3) | 3 |
|
Demand (1-3) | 3 |
|
Distinguishing Similar Minerals |
Arsenopyrite - very hard to distinguish, but
contains sulfur attributes which are lacking in
Loellingite Skutterudite, Loellingite, and Safflorite - indistinguishable without x-ray analysis. Pyrite, Marcasite, and Pyrhottite - occur in different crystals, more yellow in color |
|
Commonly Occurs With |
Loellingite, Chloanthite, Silver |
|
Noteworthy Localities |
Rammelsbergite is a rare mineral, and its
localities are limited. Occurrences include Kongsberg,
Norway; Alsace, France; Schneeberg, Saxony, Germany;
Binntal, Switzerland; and Bou Azzer, Morocco. It was found in Mexico in Batopilas, Chihuahua. In Canada it occurs in the Eldorado mine near the Great Bear Lake, Northwestern Territories, and in Cobalt, Timiskaming District, Ontario. In the U.S., it was found in the Mohawk mine, Keweenaw Co., Michigan, and in the Trotter mine, Franklin, Sussex Co., New Jersey. |
|
Picture Icon Links |
Sorry. No Images currently available. |
|
Picture Links | Sorry. No Images currently available. |
