May 16 2013
Ramsdellite is named after the American mineralogist Lewis S Ramsdell of the University of Michigan. He was the first person to describe the mineral. It is formed by pyrolusite inversion or conducting oxidative dehydrogenation of groutite.
Chemical Formula – Mn4+O2
Properties of Ramsdellite
The following are the key properties of Ramsdellite
- Cell Data
- Space Group: Pbnm
- a = 4.533
- b = 9.27
- c = 2.866
- Z = 4
- Crystal Data
- Orthorhombic
- Point Group: 2/m 2/m 2/m
- Crystals upto 1 cm are normally as pseudomorphs similar to groutite crystals; fibrous, platy and massive
- X-ray powder pattern: 4.08 (10), 2.53 (8), 1.60 (7), 1.64 (6), 2.13 (5), 1.88 (5), 1.46 (5)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
| SiO2 |
0.36 |
0.42 |
| MnO2 |
95.02 |
97.14 |
| Al2O3 |
0.72 |
0.48 |
| Fe2O3 |
0.22 |
0.34 |
| MnO |
0.00 |
0.00 |
| ZnO |
0.25 |
n.d |
| MgO |
0.00 |
0.12 |
| Cao |
1.12 |
0.00 |
| BaO |
0.00 |
0.00 |
| Na2O |
n.d |
0.31 |
| K2O |
n.d |
0.41 |
| H2O+ |
1.39 |
|
| H2O- |
0.05 |
|
| H2O |
|
1.24 |
- Optical Properties
- Class – Biaxial
- R1-R2 : n.d
- Estimated Properties
| Electron density |
Bulk density (electron density) = 4.52 g/cm3
note: Specific gravity of ramsdellite = 4.79 g/cm3 |
| Photoelectric |
PERamsdellite = 16.61 barns/electron
U=PERamsdellite x ρElectron Density= 75.02 barns/cc |
| Fermion index |
Fermion Index = 0.0001766733
Boson Index = 0.9998233267 |
| Radioactivity |
Ramsdellite is not radioactive |
How to Identify Ramsdellite
Ramsdellite is opaque, steel gray to iron black and yellowish white in reflected light. It has a brilliant metallic luster.
Global Distribution
Ramsdellite is distributed in the following places:
- in the USA, from Lake Valley, Sierra Co New Mexico
- in the Artillery Mountains, Mohave Co., and at the Mistake mine, Yavapai Co., Arizona
- from the Idarado mine, near Telluride, San Miguel Co., Colorado
- in the Monroe-Tener mine, near Chisholm, St. Louis Co., Minnesota.
- Along the East River, Pictou Co., Nova Scotia, Canada.
- In Mexico, at Los Gavilanes, Baja California.
- In India, from Dongari Buzurg, Bhandara, Madhya Pradesh.
- At the Iron Monarch quarry, Iron Knob, South Australia.
- From the Otoshibetsu and Tanno mines, Hokkaido, and elsewhere in Japan.
- At Horni Blatna (Platten), Czech Republic
- From B¨utten-Adenstadt, Lower Saxony, and the Clara Mine, near Oberwolfach, Black Forest, Germany
- At Gebel To Yu, Yoider, and Um Bogna, Egypt
- From Hotazel, near Kuruman, Cape Province, South Africa
Occurrence of Ramsdellite and Useful Mineral Association
Ramsdellite is a secondary mineral in manganese deposits, formed by inversion of pyrolusite or oxidative dehydrogenation of groutite. It is associated with minerals such as Pyrolusite, hollandite, cryptomelane and coronadite.
References