Jun 3 2014
Borcarite is a monoclinic-prismatic mineral, containing oxygen, magnesium, hydrogen, carbon, calcium, and boron.
The mineral was named because of the BORate and CARbon in its composition.
Properties of Borcarite
The following are the key properties of Borcarite:
- Cell Data
- Space Group: C2/m
- a = 17.840(4)
- b = 8.380(2)
- c = 4.445(1)
- β = 102.04(3)°
- Z = 2
- Crystal Data
- Monoclinic
- Point Group: 2/m
- As euhedral crystals, to 5mm; in sub-parallel growths, dense massives, and in veins
- X-ray Powder Pattern: 7.57 (10), 2.67 (10), 1.886 (10), 2.91 (9), 2.27 (9), 2.21 (9), 1.610 (9)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
Content 3 |
| CaO |
41.31 |
40.50 |
41.09 |
| B2O3 |
24.77 |
25.38 |
25.51 |
| CO2 |
15.64 |
16.65 |
16.12 |
| H2O+ |
10.20 |
10.06 |
9.90 |
| MgO |
7.40 |
6.02 |
7.38 |
| FeO |
0.46 |
1.17 |
- |
| Al2O3 |
0.26 |
- |
- |
| H2O- |
0.07 |
0.20 |
- |
| Fe2O3 |
0.02 |
- |
- |
| Total |
100.13 |
99.98 |
100.00 |
- Optical Properties
- Optical Class: Biaxial (–)
- Orientation: Z = b; Y ^ c = 28(4)°
- Dispersion: r < v, noticeable
- α = 1.590–1.594
- β = 1.632–1.653
- γ = 1.641–1.660
- 2V(meas.) = 30(2)°
- 2V(calc.) = 20°
- Estimated Properties
| Electron density |
Bulk density (electron density) = 2.80 g/cm3
note: Specific gravity of Borcarite = 2.79 g/cm3 |
| Photoelectric |
PEBorcarite = 3.85 barns/electron
U = PEBorcarite x ρElectron density = 10.80 barns/cm3 |
| Fermion index |
Fermion index = 0.02
Boson index = 0.98 |
Radioactivity
|
Borcarite is not radioactive
|
How to Identify Borcarite
Borcarite can be colorless. It also can occur in a range of colors, from blue-green to green and greenish-blue. It has perfect cleavage, white streak, and a vitreous luster.
The relative density of borcarite is 2.77 g/cm3.
Global Distribution
Borcarite is distributed in the following places:
- Snezhnoye boron deposit, Izvestkovyi stream, Tas-Khayakhtakh Range, Polar Ural Mountains, Russia
- Solongo boron deposit, Buryatia, Siberia
- Fuka, near Bicchu, Okayama Prefecture, Japan
Occurrence of Borcarite and Useful Mineral Association
Borcarite is a rare secondary mineral, formed by the reaction of late hydrothermal fluids with brucite. It also occurs in kotoite marbles, near the contact with granodiorite.
References