Jun 3 2014
Surinamite is a monoclinic blue-green crystal. It was first discovered in the Bakhuis Mountains. It is a member of the sapphirine super-group of minerals.
It was named after Surinam, where the mineral was first discovered.
Properties of Surinamite
The following are the key properties of Surinamite:
- Cell Data
- Space Group: P2/n
- a = 9.916(1)
- b = 11.384(1)
- c = 9.631(1)
- β = 109.30(1)°
- Z = 4
- Crystal Data
- Monoclinic
- Point Group: 2/m
- As small crystals, platy || {010}, to 0.2mm
- X-ray powder pattern: 2.435 (100), 1.99 (100), 1.420 (80), 7.05 (60), 2.91 (60), 1.432 (60), 1.411 (60)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
| Al2O3 |
34.9 |
34.3 |
| SiO2 |
33.1 |
32.3 |
| MgO |
16.45 |
17.3 |
| FeO |
12.25 |
10.8 |
| MnO |
1.05 |
0.7 |
| ZnO |
0.05 |
- |
| TiO2 |
0.05 |
- |
| CaO |
0.05 |
- |
| F |
0.05 |
- |
| BeO |
n.d. |
[4.5] |
| Total |
[97.95] |
[99.9] |
- Optical Properties
- Optical Class: Biaxial (-)
- Pleochroism: Y = violet, || to cleavage = bright blue-green; ⊥ to cleavage = very light greenish-brown to colorless
- Orientation: Y = b
- Dispersion: Very strong
- α = 1.738
- β = 1.743
- γ = 1.746
- 2V(meas.) = 67°- 68°
- Estimated Properties
| Electron density |
Bulk density (electron density) = 3.53 g/cm3
note: Specific gravity of Surinamite = 3.59 g/cm3 |
| Photoelectricv |
PESurinamite = 3.62 barns/electron
U = PESurinamite x ρElectron density = 12.81 barns/cm3 |
| Fermion index |
Fermion index = 0.03
Boson index = 0.97 |
Radioactivity
|
Surinamite is not radioactive
|
How to Identify Surinamite
Surinamite can be found in blue, or blue-green forms. It has white streak, and good cleavage. The average density of surinamite is 3.58 g/cm3.
Global Distribution
Surinamite is distributed in the following places:
- Bakhuis Mountains, Surinam
- Woolanga Bore area, Strangways Range, Northern Territory, Australia
- Casey Bay, Enderby Land, Antarctica
- Chimwala area, Eastern Province, Zambia
Occurrence of Surinamite and Useful Mineral Association
Surinamite occurs in mylonitic mesoperthite gneiss; presumably formed during high-pressure granulite facies metamorphism of aluminous rocks, in sillimanite-rich segregations in pegmatites, and as pseudomorphs after cordierite.
It is closely associated with cordierite, taaffeite, sapphirine, sillimanite, quartz, spinel, sillimanite, kyanite, and biotite.
References