Dzierżanowskite
Chemical formula: CaCu₂S₂
Dzierżanowskite is a very rare calcium-copper sulfide, forming tiny, metallic inclusions in metamorphic rocks.
Properties
- Color
- Dark orange
- Luster
- Metallic
- Streak
- Cream
- Density
- 4.391
- Transparency
- Opaque
- Crystal system
- Trigonal
Diagnostic features
## Identification Identification of dzierżanowskite is possible almost exclusively using advanced laboratory techniques, such as reflected light ore microscopy and X-ray microanalysis (EDS/WDS). In reflected light, it exhibits a characteristic brownish-pink color, distinct anisotropy, and pleochroism. ## Distinguishing from Similar Minerals Under the microscope, it can be confused with other fine copper sulfides, such as chalcocite or digenite. Definitive differentiation requires chemical composition analysis, which will reveal the presence of calcium – an element atypical for this group of minerals. ## Crystal Forms Dzierżanowskite forms only anhedral (irregular) grains and lamellae ranging from 5 to 100 micrometers in size, occurring as inclusions in other minerals, mainly diopside.
Geological environment
## Genesis Dzierżanowskite forms under conditions of contact metamorphism. It was discovered in rodingites – rocks formed as a result of calcium-silicate metasomatism of gabbroic rocks within an ophiolite complex. Its formation is associated with hydrothermal processes occurring in subduction zones. ## Mineral Associations It co-occurs with minerals such as diopside, titanite, chalcocite, digenite, covellite, chlorite group minerals, and garnets (andradite). ## Localities The only confirmed occurrence of dzierżanowskite in the world (type locality) is the Khan-Taishir ophiolite complex in the Govi-Altai Aimag in southwestern Mongolia.
Rarity
Extremely rare
For collectors
## Quality Criteria As a microscopic mineral, dzierżanowskite is not evaluated according to typical collecting criteria, such as crystal size or form. The value of a specimen lies in its scientific significance and the confirmed presence of the mineral in the rock matrix. The most valuable specimens are those from the type locality, with accurately documented chemical analysis, often in the form of professionally prepared petrographic thin sections.
Care and storage
## Cleaning Specimens containing dzierżanowskite, which are usually polished thin sections or rock slabs, should be cleaned only with a dry, soft microfiber cloth to avoid scratches and damage to the delicate surface. ## What to Avoid Avoid contact with chemicals, acids, detergents, and ultrasonic cleaners. As a sulfide, the mineral is susceptible to oxidation and chemical reactions. It should be protected from moisture and sudden temperature changes. ## Storage Specimens should be stored in a dry place, preferably in a closed display box or cabinet, away from direct sunlight and dust. Due to the microscopic size of the grains, specimens are most often in the form of microscopic preparations or rock thin sections, which require careful handling.