Jun 13 2014
Topics Covered
Introduction to Adelite
Properties of Adelite
How to Identify Adelite
Global Distribution
Occurrence of Adelite and Useful Mineral Association
References
Introduction to Adelite
Chemical Formula – CaMg (AsO4)(OH)
Adelite was named after the Greek word for indistinct, due to the fact that the mineral lacks transparency.
Properties of Adelite
The following are the key properties of Adelite:
- Cell Data
- Space group: P212121
- a = 7.43
- b = 8.85
- c = 5.88
- Z = 4
- Crystal Data
- Orthorhombic
- Point group: 222
- Tabular on {001}, or elongated along [100], showing {100}, {001}, {110}, {011}, {221}, to 5mm
- May be hemispherulitic
- Commonly granular, massive
- X-ray powder pattern: 3.16 (10), 4.13 (7), 2.59 (7), 2.33 (7), 1.609 (7), 4.96 (6), 2.98 (6)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
| As2O5 |
50.28 |
52.17 |
| CaO |
24.04 |
25.45 |
| MgO |
17.90 |
18.30 |
| H2O |
3.90 |
4.08 |
| PbO |
2.79 |
- |
| MnO |
0.48 |
- |
| CuO |
0.32 |
- |
| BaO |
0.23 |
- |
| FeO |
0.08 |
- |
| Cl |
Trace |
- |
| Total |
100.02 |
100.00 |
- Optical Properties
- Translucent to transparent
- Optical class: Biaxial (+)
- Orientation: X = a; Y = c; Z = b
- Dispersion: r < v , weak
- α = 1.712; β = 1.721; γ = 1.731
- 2V(meas.) = 68° to ~90°
- Estimated Properties
| Electron density |
Bulk density (electron density) = 3.62 g/cm3
note: Specific gravity of Adelite = 3.76 g/cm3. |
| Photoelectric |
PEAdelite = 25.46 barns/electron
U = PEAdelite x ρ electron density = 92.10 barns/cm3 |
| Fermion index |
Fermion index = 0.01
Boson index = 0.99 |
Radioactivity
|
Adelite is not radioactive
|
How to Identify Adelite
Adelite can be identified in the field by its color variations, such as blue-gray, green, gray, yellow, and light green. It is transparent, with indistinct cleavage. This mineral has a resinous luster, with a white streak. The fracture on this mineral is conchoidal. It has a non-fluorescent luminescence.
The density of Adelite is 3.73 to 3.79 g/cm3, with a hardness of 5 – approximate to apatite.
Global Distribution
Adelite is distributed in the following places:
- Sweden - From Langban and at Jakobsberg, Varmland, and in the Kittel mine, Nordmark
- Germany - At St. Andreasberg, Harz Mountains
- USA - From Sterling Hill, Ogdensburg, and Franklin, Sussex Co. New Jersey
Occurrence of Adelite and Useful Mineral Association
Adelite occurs in a rare mineral in a metamorphosed Fe–Mn orebody; and on willemite-franklinite ore from a metamorphosed stratiform zinc orebody.
It is often associated with minerals such as arsenoclasite, sarkinite, braunite, fredrikssonite, hedyphane, hausmannite, magnetite, copper, hodgkinsonite, barite, rhodochrosite, allactite, franklinite, willemite, alleghanyite, kraisslite, sphalerite, chlorophoenicite, rhodochrosite, willemite, franklinite; johnbaumite–svabite, zincite, barite, and calcite.
References