Colinowensite

Chemical formula: BaCu²⁺Si₂O₆

Colinowensite is a rare barium-copper silicate with a characteristic purple color, occurring as microscopic crystals.

## Characteristics Colinowensite is a very rare mineral from the silicate group, chemically classified as a barium-copper silicate. It occurs as very small, tabular or platy crystals, rarely exceeding fractions of a millimeter. Its most characteristic feature is an intense purple color, which in thicker fragments can transition to dark blue. It usually forms small aggregates or appears as single, scattered crystals on the surface of other minerals. ## Physical Properties The hardness of colinowensite on the Mohs scale is 4. It is an opaque mineral with a density of 4.20 g/cm³. Its fracture is uneven. The streak, which is the color of the powdered mineral, is purple. ## Colors and Varieties This mineral is monochromatic – it takes on shades from purple to dark blue. No color varieties or commercial varieties are distinguished. ## History and Name Colinowensite was first described in 2013. Its name honors Colin Owens (born 1950), a renowned mineral collector from South Africa, who specialized in specimens from the Kalahari Manganese Fields region and was the first to notice this mineral. ## Uses Due to its extreme rarity and microscopic crystal sizes, colinowensite has no industrial applications. It is solely an object of scientific and collecting interest for specialized collectors of rare minerals (so-called micromounts).

Properties

Mohs hardness: 4
Streak: Purple
Density: 4.20
Fracture: Irregular/Uneven
Transparency: Opaque
Crystal system: Tetragonal

Diagnostic features

## Identification Colinowensite is recognizable primarily by its unique, intense purple color, purple streak, and specific occurrence. Field identification is practically impossible due to the size of the crystals. Definitive identification requires advanced analytical methods, such as Raman spectroscopy or EDS analysis. ## Distinguishing from Similar Minerals Due to its unique color and mineral associations, it is difficult to confuse with other minerals in its typical locality. Theoretically, other rare copper minerals with violet colors might be similar, but the geological context and co-occurring minerals (such as sugilite) are key for differentiation. ## Crystal Forms It forms very small, thin, tabular crystals with a tetragonal outline, often with truncated corners. These crystals usually occur as single, scattered plates or form small, rosette-like aggregates.

Geological environment

## Genesis Colinowensite is a hydrothermal mineral, formed in metamorphosed manganese deposits. It crystallizes in the late stage of mineral-forming processes, filling small fissures and pores in the rock. ## Mineral Associations This mineral co-occurs with other rare minerals in the Wessels Mine. It is most often found in association with sugilite, quartz, and other rare silicates and manganese oxides. ## Localities The only confirmed locality of colinowensite in the world is its type locality – the Wessels Mine in the Kalahari Manganese Fields region of the Northern Cape Province in the Republic of South Africa.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a colinowensite specimen is assessed based on the intensity and saturation of the purple color of the crystals, their size (though always small), and their abundance on the rock matrix. The most prized specimens are those with well-formed, undamaged crystals forming rich aggregates on a contrasting background, for example, on light sugilite or quartz. ## Popular Localities All known collector specimens come from a single location worldwide: the Wessels Mine in South Africa. This is the only source of this mineral.

Care and storage

## Cleaning Specimens containing colinowensite should be handled with the utmost care. Due to the microscopic size of the crystals, mechanical cleaning is not recommended. If absolutely necessary, compressed air (from a safe distance) can be used to remove dust. Avoid contact with water and any chemicals. ## What to Avoid Avoid ultrasonic cleaners, chemical agents, acids, and sudden temperature changes. The mineral is fragile and susceptible to mechanical damage. ## Storage Specimens should be stored in stable conditions, in sealed "micromount" boxes, to protect them from dust and physical damage. It is not sensitive to light, but protection from external factors is crucial for preserving the delicate crystals.

External references

https://www.mindat.org/min-43366.html