Editorial Feature

Calciborite – Occurrence, Properties, and Distribution

Oct 14 2013

Calciborite was named after the chemical components in its composition - Calcium and Boron.

Properties of Calciborite

The following are the key properties of calciborite:

Cell Data
- Space group: Pccn
- a = 8.38
- b =13.81
- c = 5.00
- Z = 8
Crystal Data
- Orthorhombic.
- Point group: 2/m2/m2/m.
- Prismatic crystals, to 1.5 cm, in radial clusters and bundles, intimately inter-grown with sibirskite.
- X-ray powder pattern: 3.44 (10), 3.57 (8), 1.976 (7), 1.870 (7), 1.793 (7), 7.10 (6), 3.81 (6).

Chemical Composition

Elements	Content 1	Content 2
B₂O₃	47.58	55.39
CaO	44.08	44.61
CO₂	6.07	-
MgO	0.81	-
SiO₂	0.55	-
H₂O^-	0.50	-
As₂O₅	0.30	-
Fe₂O₃	0.22	-
Al₂O₃	0.18	-
H₂O⁺	0.17	-
Total	100.46	100.00

Optical Properties
- Optical class: Biaxial (-)
- Orientation: Extinction angle 22°
- α = 1.595; β = 1.654; γ = 1.670
- 2V(meas.) =54°

Estimated Properties

Electron density	Bulk density (electron density) = 2.85 g/cm³ note: Specific gravity of calciborite = 2.89 g/cm³
Photoelectric	PE_Calciborite = 4.14 barns/electron U=PE_Calciborite x ρ electron density= 11.79 barns/cm³
Fermion index	Fermion index = 0.03 Boson index = 0.97
Radioactivity	Calciborite is not radioactive.

How to Identify Calciborite

Calciborite can be identified in the field by its white color and white streak. This mineral has no cleavage, and a conchoidal, uneven fracture. The density of calciborite is 2.878 g/cm³ with a hardness of 3.5 – approximate to a copper penny.

Global Distribution

Calciborite is distributed mainly in Russia, from the Novofrolovskoye copper deposit, near Krasnoturinsk, Turinsk district, Northern Ural Mountains.

Occurrence of Calciborite and Useful Mineral Association

Calciborite occurs from drillcore into a contact metasomatised limestone near a quartz diorite intrusion associated with a copper deposit in skarn. It is often associated with minerals such as sibirskite, calcite, dolomite, pyroxene, garnet, and magnetite.