Clino-oscarkempffite
Chemical formula: Ag¹⁺₁₅Pb²⁺₆Sb³⁺₂₁Bi³⁺₁₈S²⁻₇₂
A rare sulfosalt of lead, silver, antimony, and bismuth, forming acicular crystals with a metallic luster.
Properties
- Mohs hardness
- 3-3.5
- Luster
- Metallic
- Streak
- Dark grey
- Density
- 6.04
- Fracture
- Irregular/Uneven
- Transparency
- Opaque
- Crystal system
- Monoclinic
Diagnostic features
## Identification Characteristic features include acicular crystal habit, grayish-black color, metallic luster, and a dark gray streak. High density is also an important indicator. However, final identification requires advanced analytical methods, such as chemical composition analysis (EDS) and X-ray diffraction (XRD). ## Distinguishing from Similar Minerals It can be confused with other acicular sulfosalts, such as jamesonite, boulangerite, or other minerals from the lillianite group. Differentiation by eye is practically impossible and requires specialized laboratory equipment to confirm the presence and proportions of silver, lead, antimony, and bismuth. ## Crystal Forms It forms prismatic, acicular crystals, elongated along one axis. These crystals often occur as tangled or radial aggregates.
Geological environment
## Genesis This is a hydrothermal mineral, crystallizing in ore veins formed under moderate temperature conditions. It forms in polymetallic deposits rich in antimony, bismuth, silver, and lead. ## Mineral Associations At the type locality (Ánimas mine), it coexists with other sulfosalts, such as andorite, fizélyite, miargyrite, pyroxenite, as well as with pyrite, sphalerite, galena, and quartz. ## Localities The only confirmed and described occurrence of this mineral in the world is its type locality: the Colorada vein in the Ánimas mine, in the Chocaya-Animas mining district, Potosí Department, Bolivia.
Rarity
Extremely rare
For collectors
## Quality Criteria As an extremely rare mineral, any well-formed and analytically confirmed specimen is valuable. The most desirable samples are those with clearly visible, undamaged acicular crystals, preferably forming aesthetic aggregates on a rock matrix. Association with other rare sulfosalts is also important. ## Popular Localities The only source of specimens is the Ánimas mine in Bolivia, which is known for providing many rare and well-crystallized sulfosalts. Specimens from this locality are highly prized by collectors specializing in systematic mineralogy.
Care and storage
## Cleaning Specimens should only be cleaned mechanically, using a soft brush to remove dust. Due to its rarity and potential reactivity, contact with water and any chemical agents should be avoided. ## What to Avoid Avoid contact with chemicals, acids, and detergents, which can damage the mineral's surface. As a sulfosalt, it may be sensitive to moisture and oxidation in the long term. Protect it from high temperatures and sudden temperature changes. ## Storage It is recommended to store specimens in dry conditions, preferably in closed, padded collector boxes or display cases, to minimize the risk of mechanical damage and limit air exposure.