May 19 2014
Diopside is a monoclinic pyroxene mineral that first described in 1800.
The mineral derives its name from the Greek words dis and opse, which mean twice and face, in reference to the two ways of orienting the vertical prism.
Properties of Diopside
The following are the key properties of Diopside:
- Cell Data
- Space Group: C2/c
- a = 9.746
- b = 8.899
- c = 5.251
- β = 105.63°
- Z = 4
- Crystal Data
- Monoclinic
- Point Group: 2/m
- As prismatic crystals with nearly square cross sections, to 50cm; granular, columnar, lamellar massive
- Twinning: Simple or multiple twins on {100} or {010}, common
- X-ray Powder Pattern: 2.991 (100), 2.528 (40), 2.893 (30), 2.518 (30), 3.23 (25), 2.952 (25), 1.625 (25)
- Chemical Composition
| Elements |
Content |
| SiO2 |
54.66 |
| CaO |
25.85 |
| MgO |
18.78 |
| Cr2O3 |
2.03 |
| Na2O |
1.37 |
| Fe2O3 |
0.68 |
| TiO2 |
0.28 |
| H2O+ |
0.22 |
| K2O |
0.15 |
| H2O- |
0.08 |
| FeO |
0.07 |
| Al2O3 |
0.07 |
| MnO |
0.02 |
| rem |
0.49 |
| Total |
100.35 |
- Optical Properties
- Optical Class: Biaxial (+)
- Orientation: Y = b; Z ^ c = -38° on (010); X ^ a = -22°
- Dispersion: r > v; weak to moderate
- α = 1.664
- β = 1.672
- γ = 1.694
- 2V(meas.) = 59°
- Estimated Properties
| Electron density |
Bulk density (electron density) = 3.39 g/cm3
note: Specific gravity of Diopside = 3.40 g/cm3 |
| Photoelectric |
PEDiopside = 3.51 barns/electron
U = PEDiopside x ρElectron density = 11.91 barns/cm3 |
| Fermion index |
Fermion index = 0.02
Boson index = 0.98 |
Radioactivity
|
Diopside is not radioactive
|
How to Identify Diopside
Global Distribution
Diopside is distributed in the following places:
- Schwarzenstein, Zillertal, and near PrÄagraten, Tirol, Austria
- Ala, Piedmont, and St. Marcel, Val d'Aosta, Italy
- Otokumpu, Finland
- Akhmatovsk deposit, near Zlatoust, Ural Mountains, Russia
- Inagli massif, 30km west of Aldan, Yakutia
- Slyudyanka River, near Lake Baikal, Siberia
- Bird's Creek, Eganville, Dog's Lake, Littlefield, and Burgess, Ontario, Canada
- Wakefield, Brompton Lake, near Magog, Quebec
- Jeffrey mine, Asbestos
- DeKalb, St. Lawrence Co. Natural Bridge, USA
- Jefferson Co. Sing Sing, near Ossining, Westchester Co. New York
- Ducktown, Polk Co. Tennessee
- Ampandrandava and Andranodambo, Taola Änaro (Fort Dauphin), Madagascar
- Kunlun Mountains, Sinkiang Uighur Autonomous Region, China
- Tange-Achin, Kandahar Province, Afghanistan
- Jaipur, Rajasthan, India
- Khapalu and Chamachu, Pakistan
Occurrence of Diopside and Useful Mineral Association
Diopside occurs in metamorphosed siliceous Ca, Mg-rich rocks of the pyroxene-hornfels, or epidote-amphibolite facies, skarns, Ca, Mg-rich gneisses and schists, and some kimberlites and peridotites. It is less common in andesites and alkalic olivine basalts.
References