Bukovite
Chemical formula: (Cu<sup>1+</sup><sub>3</sub>Fe<sup>3+</sup>)Tl<sup>1+</sup><sub>2</sub>Se<sup>2-</sup><sub>4</sub>
Bukovite is a very rare, hydrothermal copper, iron, and thallium selenide, forming tiny, metallic-lustered grains in association with other selenides.
Properties
- Mohs hardness
- 2-2.5
- Luster
- Metallic
- Streak
- Black
- Density
- 7.37
- Cleavage
- None
- Fracture
- Uneven
- Transparency
- Opaque
- Crystal system
- Tetragonal
Diagnostic features
## Identification Identification of bukovite is almost exclusively possible using advanced laboratory methods, such as chemical composition analysis (EDS/WDS) and X-ray diffraction (XRD). A preliminary indication may be its reddish-gray color, metallic luster, and co-occurrence with other rare selenides in calcite veins. ## Distinguishing from Similar Minerals It can be confused with other rare selenides, such as berzelianite, umangite, or clausthalite. Berzelianite has a similar luster but is more bluish-gray. Umangite has a characteristic purplish-red color. However, definitive differentiation requires chemical analysis, especially confirmation of the presence of thallium and iron. ## Crystal Forms Bukovite forms only very fine, irregular grains and aggregates, often as inclusions in other minerals. Well-formed crystals are not observed.
Geological environment
## Genesis Bukovite is a mineral of hydrothermal origin. It forms at low to medium temperatures in calcite-dolomite veins, cutting through uranium and polymetallic deposits. Its crystallization is associated with selenide mineralization processes. ## Mineral Associations This mineral co-occurs with other selenides, such as berzelianite, eskebornite, umangite, clausthalite, as well as with uraninite, hematite, pyrite, and chalcopyrite. The gangue mineral is usually calcite or dolomite. ## Localities The most important and type locality for bukovite is Bukov in the Rožná area of Moravia, Czech Republic. It is also known from the Předbořice uranium mine in central Bohemia and from a selenide vein in Paczków, Lower Silesia, Poland. Outside Europe, its presence has been reported in the Trixie mine in Utah, USA.
Rarity
Very rare
For collectors
## Quality Criteria As a micromineral, bukovite is not evaluated based on typical criteria such as size or crystal purity. The most valuable specimens for collectors are those where bukovite grains are relatively large (for this mineral, meaning fractions of a millimeter), clearly visible, and richly accumulated. Association with other rare selenides on the same rock fragment is also of great importance. ## Popular Localities The most classic and prized specimens come from the type locality in the Czech Republic (Bukov, Rožná). Specimens from other confirmed localities, such as Předbořice or Paczków, are also sought after by specialized collectors.
Care and storage
## Cleaning Specimens containing bukovite, typically microminerals, do not require cleaning. If absolutely necessary, compressed air can be used to remove dust. Avoid contact with water and chemicals. ## What to Avoid As a thallium-bearing mineral, bukovite is potentially toxic. Avoid inhaling dust and direct skin contact. Always wash hands after handling a specimen. Protect it from acids and other chemical reagents. ## Storage Specimens containing bukovite should be stored in specialized micromount boxes, away from moisture and dust. Clear labeling of the specimen is necessary due to thallium toxicity.