Jun 11 2014
Calumetite was named after the town of Calumet in Michigan, USA, where it was first discovered.
Properties of Calumetite
The following are the key properties of calumetite:
- Crystal Data
- Orthorhombic
- Point group: n.d
- As spherules and sheaves of scaly crystals, sub-parallel on {001}, with {001} and {110}
- X-ray powder pattern: 7.50 (10), 2.481 (8), 3.02 (6), 3.76 (5), 3.42 (3), 3.30 (3), 2.341 (3)
- Chemical Composition
| Elements |
Content |
| Cu |
44.1 |
| H2O+ + OH |
33.5 |
| H2O+ |
16.9 |
| Cl |
5.3 |
| AgCl |
0.17 |
| Total |
99.97 |
- Optical Properties
- Optical class: Biaxial (-)
- Pleochroism: Feeble; in blues
- Orientation: X = c; Y = a; Z = b
- Absorption: Z _ Y > X
- α = 1.666; β = 1.690; γ = 1.690
- 2V(meas.) = 2°
- Estimated Properties
| Photoelectric |
PECalumetite = 19.45 barns/electron |
| Fermion index |
Fermion index = 0.000156509
Boson index = 0.999843491 |
| Radioactivity |
Calumetite is not radioactive |
How to Identify Calumetite
Calumetite can be identified in the field by its color variations, such as azure-blue, powder blue, and bluish-white. Its opaque form has {001} perfect cleavage. This mineral has a pearly luster, with blue streak. The fracture on this mineral is brittle.
The density of calumetite is 7.2 to 7.4 g/cm3, with a hardness of 2 - approximate to gypsum.
Global Distribution
Calumetite is distributed in the following places:
- USA - From the Centennial and other nearby mines, near Calumet, Houghton Co. Michigan
- Greece - From Laurium, in slag
- Germany - From Niederfischbach, Siegerland, and at Richelsdorf, Hesse, in slag
Occurrence of Calumetite and Useful Mineral Association
Calumetite occurs in cavities and fractures in basalt, formed by the action of chlorine-bearing connate waters on copper, with cuprite being regarded as an intermediate product in the alteration.
It is often associated with minerals such as tremolite, monazite, quartz, epidote, copper, cuprite, paratacamite, atacamite, buttgenbachite, malachite, and anthonyite.
References