May 28 2014
Carboborite was named after the key anionic chemical components - CARBOnate and BORate.
Properties of Carboborite
The following are the key properties of carboborite:
- Cell Data
- Space group: P21/n
- a = 11.011(3)
- b = 6.674(1)
- c = 10.692(5)
- β = 116.64(3)°
- Z = 2
- Crystal Data
- Monoclinic
- Point group: 2/m
- As steep pseudorhombohedral crystals, to 3mm, with dominant {101} and {110}, modified by {011}, {100}, {121}, and {101}
- X-ray powder pattern: 5.63 (10), 4.315 (10), 3.136 (8), 2.160 (8), 2.727 (7), 2.437 (6), 4.86 (5)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
| H2O |
39.78 |
31.73 |
| CaO |
24.21 |
24.69 |
| B2O3 |
15.70 |
15.33 |
| CO2 |
10.46 |
19.38 |
| MgO |
9.08 |
8.87 |
| insol. |
1.17 |
- |
| Na2O |
0.27 |
- |
| K2O |
trace |
- |
| Cl |
0.00 |
- |
| SO3 |
0.00 |
- |
| Total |
100.67 |
100.00 |
- Optical Properties
- Optical Class: Biaxial (–)
- Orientation: Y = b; X ^ a = 10°19’; Z ^ c = 12°
- α = 1.507(1); β = 1.546(1); γ = 1.569(1)
- 2V(meas.) = 75°
- Estimated Properties
| Electron density |
Bulk density (electron density) = 2.22 g/cm3
note: Specific gravity of carboborite = 2.15 g/cm3 |
| Photoelectric |
PECarboborite = 2.45 barns/electron
U=PECarboborite x ρ electron density = 5.42 barns/cm3 |
| Fermion index |
Fermion index = 0.01
Boson index = 0.99 |
Radioactivity
|
Carboborite is not radioactive
|
How to Identify Carboborite
Carboborite can be identified in the field by its colorless structure. Its transparent form has a vitreous luster with white streak.
The density of carboborite is 2.12 g/cm3 with a hardness of 2 – approximate to gypsum.
Global Distribution
Carboborite is distributed in the following places:
- China - At an unspecified locality, possibly at Dafangshan, Qinghai Plateau, Tibet
- USA – California, Inyo Co. Death Valley National Park, Death Valley USGS, Furnace Creek District (Furnace Creek Borate District)
Occurrence of Carboborite and Useful Mineral Association
Carboborite typically occurs in a lacustrine borate deposit.
It is often associated with minerals such as ulexite, hydroboracite, and gypsum.
References