Sep 26 2013
Brodtkorbite was named after Dr. Milka Kronegold de Brodtkorb, Professor at the Universities of Buenos Aires and La Plata, Argentina, in recognition to her contributions to mineralogy and economic geology.
Properties of Brodtkorbite
The following are the key properties of brodtkorbite:
- Cell Data
- Space group: P21/n
- a = 7.492(5)
- b = 4.177(1)
- c = 7.239(4)
- β = 114.20(5)°
- Z = 2
- Crystal Data
- Monoclinic
- Point group: 2/m
- As individual anhedral grains, to 100 µm, and in aggregates
- X-ray powder pattern: 2,730 (100), 3.991 (70), 2.223 (70), 3.576 (50), 3.534 (50), 3.414 (50), 2.072 (50)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
| Hg |
40.7 |
41.31 |
| Se |
32.9 |
32.52 |
| Cu |
26.2 |
26.17 |
| Total |
99.8 |
100.00 |
- Optical Properties
- Anisotropism: Weak to strong; mauve-gray to yellowish gray
- Optical class: Biaxial
- Pleochroism: Weak to moderate; pale pink to pale blue
- Bireflectance: Weak to strong
- R1–R2: (400) 30.7–38.1, (420) 30.6–38.2, (440) 30.4–37.9, (460) 29.9–37.3, (480) 29.3–36.6, (500) 28.6–36.0, (520) 28.0–35.6, (540) 27.5–35.2, (560) 27.1–35.0, (580) 26.8–34.8, (600) 26.4–34.5, (620) 26.2–34.3, (640) 26.1–34.2, (660) 26.1–33.9, (680) 26.3–33.6, (700) 26.4–33.3
- Estimated Properties
| Electron density |
Bulk density (electron density) = 6.62 g/cm3
note: Specific gravity of brodtkorbite = 7.80 g/cm3 |
| Photoelectric |
PEBrodtkorbite = 728.96 barns/electron
U = PEBrodtkorbite x ρ electron density = 4,824.10 barns/cm3 |
| Fermion index |
Fermion index = 0.14
Boson index = 0.86 |
|
Radioactivity
|
Brodtkorbite is not radioactive. |
How to Identify Brodtkorbite
Brodtkorbite can be identified in the field by its dark gray color. This mineral is opaque and has no cleavage. This mineral has a metallic luster with dark gray streak. The fracture on this mineral is brittle and uneven. The density of brodtkorbite is 7.77 g/cm3 with a hardness of 2.5-3 - between finger nail and calcite.
Global Distribution
Brodtkorbite is distributed mainly in Argentina from Tuminico, Sierra de Cacho in La Rioja Province.
Occurrence of Brodtkorbite and Useful Mineral Association
Brodtkorbite occurs rarely in a telethermal selenium-rich hydrothermal polymetallic deposit, and in calcite veins in amphibolites, formed below 112°C. It is often associated with minerals such as berzelianite, umangite, clausthalite, tiemannite, eucairite, hematite, naumannite, and calcite.
References