Aug 14 2013
Zussmanite was discovered in the year 1964 in the Laytonville Quarry located in the Coastal Range of California, USA. This mineral is named after Jack Zussman, who is a professor at the University of Manchester in England. Zussmanite is isostructural and the Fe-analogue of Coombsite.
Properties of Zussmanite
The key physical properties of Zussmanite are summarised below:
- Cell Data
- Space Group - R3 or R3
- a= 11.6 (2)
- c=28.69 (2)
- Z = 3
- Crystal Data
- Hexagonal
- Point Group – 3 or 3
- Crystals – tabular crystals to about 1 mm.
- X-ray powder pattern: Laytonville district, California, USA
9.60 (100), 4.78 (45), 3.19 (25), 2.51 (16), 3.78 (10), 2.74 (10), 2.20 (10).
- Chemical Composition
| Elements |
Content 1 |
| K2O |
2.19 |
| MgO |
1.88 |
| MnO |
3.30 |
| Al2O3 |
2.37 |
| FeO |
36.81 |
| SiO2 |
47.57 |
| H2O |
5.87 |
- Optical Properties
- Translucent
- Lustre – vitreous
- Color- pale green in thin section
- Optical Class – Uniaxial (-)
- Estimated Properties
| Electron density |
Bulk density (electron density) = 3.09 g/cm3
note: Specific gravity of Zussmanite = 3.15 g/cm3 |
| Photoelectric |
PEZussmanite = 10.23 barns/electron
U = PEZussmanite x rho;electron density = 31.62 barns/cm3 |
| Fermion index |
Fermion index = 0.01
Boson index = 0.99 |
|
Radioactivity
|
GRapi = 25.83 (Gamma Ray American Petroleum Institute Units)
Concentration of Zussmanite per GRapi unit = 3.87 %
Radioactivity of Zussmanite is barely detectable. |
How to Identify Zussmanite
The color of zussmanite is pale green in the thin section. This mineral also exhibits a vitreous lustre.
Global Distribution
Zussmanite is found only in the Laytonville quarry located in the Mendocino Co in California, USA.
Occurrence of Zussmanite and Useful Mineral Association
Zussmanite occurs as an exotic block of metamorphosed shales, siliceous ironstones and also impure limestones. This could probably be the representation of the deep ocean sediments that are subjected to blueschist facies metamorphism.
Zussmanite is often associated with minerals such as howieite, spessartine, aegirine, riebeckite, graphite, aragonite etc.
References