Tivanite
Chemical formula: Ti⁴⁺V³⁺O₃(OH)
Tivanite is a rare titanium and vanadium oxide, forming tiny, black crystals with a metallic luster.
Properties
- Mohs hardness
- 5.5
- Color
- Black
- Luster
- Metallic
- Streak
- Black
- Density
- 0
- Cleavage
- Good on {110}
- Fracture
- Uneven
- Transparency
- Opaque
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identifying tivanite under amateur conditions is very difficult due to its rarity and small crystal size. Key features include its black color, metallic luster, high hardness, and characteristic form of small, prismatic or acicular crystals. Definitive identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical microanalysis (EDS). ## Distinguishing from Similar Minerals It can be confused with other black, metallic-lustered acicular minerals, such as rutile, ilmenite, goethite, or tourmaline (schorl). Differentiation relies on chemical analysis of its composition (presence of titanium and vanadium) and crystallographic data. Its occurrence in a specific geological environment (quartz-carbonate veins in gold-bearing rocks) is also an important clue. ## Crystal Forms Tivanite forms elongated, prismatic crystals with a cross-section similar to a square, often terminated by a pyramid. Crystals are usually striated parallel to the elongation axis. They occur as single inclusions or in the form of small, radial aggregates.
Geological environment
## Genesis Tivanite forms under hydrothermal conditions. It has been found in quartz-carbonate veins cutting through gold-bearing rocks. Its presence is associated with potassic metasomatism, a process of rock alteration by potassium-rich solutions. ## Mineral Associations At its type locality (Kalgoorlie), tivanite co-occurs with quartz, roscoelite (vanadium mica), native gold, pyrite, chalcopyrite, coloradoite, calaverite, krennerite, petzite, sylvanite, native tellurium, altaite, melonite, and ilmenite. ## Localities The only confirmed and thoroughly described occurrence of tivanite in the world is its type locality – the West Orion gold mine in the Kalgoorlie-Boulder region of Western Australia.
Rarity
Very rare
For collectors
## Quality Criteria As a mineral of microscopic dimensions, tivanite is valued primarily for the mere fact of its presence in a specimen. The most highly rated samples are those in which tivanite crystals are well-formed, visible to the naked eye (which is rare), and contrast with the light background of the host rock, for example, quartz. Specimens from the documented type locality are particularly desirable. ## Popular Localities The only source of collector specimens is the historic type locality in Western Australia. This mineral is extremely difficult to acquire on the market.
Care and storage
## Cleaning Due to the small size of the crystals and their occurrence within the host rock, mechanical cleaning is usually neither necessary nor recommended. If needed, specimens can be rinsed in distilled water and gently dried with compressed air. ## What to Avoid Avoid contact with strong acids and chemicals, which could damage both tivanite and associated minerals. Despite its high hardness, small crystals are brittle and susceptible to mechanical damage. ## Storage Tivanite specimens are best stored in stable conditions, in closed display boxes, to protect them from dust and mechanical damage. It is not sensitive to light.