Bassoite

Chemical formula: SrV<sup>4+</sup><sub>3</sub>O<sub>7</sub>·4H<sub>2</sub>O

Bassoite is an extremely rare vanadium mineral with an intensely red color, forming microscopic, tabular crystals.

## Characteristics Bassoite is a hydrated strontium vanadate, distinguished by its vivid, red color. It occurs as very small, tabular or bladed crystals, rarely exceeding 0.2 mm in length. These crystals form rosetted or radial aggregates, as well as thin coatings on the surface of the host rock. Due to its microscopic size, it is a mineral primarily accessible to specialized micromount collectors. ## Physical Properties Bassoite crystals exhibit a vitreous luster. They are transparent to translucent. Hardness and density have not been precisely determined due to the small size and rarity of the material. ## Colors and Varieties This mineral is characterized by a uniform, intensely red color. No varieties are known. ## History and Name Bassoite was discovered at the Big Creek mine in Fresno County, California (USA) and described in 2009 by Anthony R. Kampf, Joe Marty, William S. Wise, Stuart J. Mills, and Robert A. Bass. The mineral is named in honor of Robert A. Bass (born 1950), an American mineral collector who first found this mineral and provided material for research. ## Uses Bassoite has no industrial application. Its significance is purely scientific and collectible, being an object of desire among collectors specializing in microscopic minerals (so-called "micromounts").

Properties

Luster
Vitreous
Streak
Red
Cleavage
Perfect on {010}
Fracture
Uneven
Transparency
Transparent to Translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Bassoite is identifiable by its characteristic, intensely red color, its form as small, tabular crystals forming rosetted aggregates, and its unique chemical composition. Identification requires advanced analytical methods, such as Raman spectroscopy or EDS analysis, due to the microscopic size of the crystals. ## Distinguishing from Similar Minerals It can be confused with other red secondary minerals occurring in the same environment, such as grantite or hewettite. Distinguishing "by eye" is practically impossible and requires chemical analysis. Bassoite is distinguished by the presence of strontium in its composition, which is a key diagnostic feature. ## Crystal Forms Bassoite crystals are very small, usually less than 0.2 mm in length. They have the form of thin, flattened tablets or blades. They most often occur as radial or rosetted aggregates, as well as thin coatings on the host rock.

Geological environment

## Genesis Bassoite is a secondary mineral, forming in the oxidation zones of vanadium deposits. It forms in vugs and fractures in siliceous rocks (cherts) containing quartz and sanbornite. Its formation is a result of low-temperature hydrothermal processes. ## Mineral Associations This mineral co-occurs with other rare vanadium and barium minerals. It is most often associated with: quartz, sanbornite, celsian, alforsite, macquartite, cerchiaraite-(Mn), hewettite, grantite, ruizite, and picropharmacolite. ## Localities The only confirmed locality for bassoite worldwide is its type locality – the Big Creek mine (Rush Creek), located in Fresno County, California, USA. This is one of the most famous sites for rare barium, vanadium, and silicon minerals.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a bassoite specimen is primarily assessed based on the richness and aesthetics of the crystal aggregates. Most prized are specimens with numerous, well-formed, rosetted aggregates of intense red color, clearly contrasting with the light background of the host rock. Due to the microscopic nature of the mineral, the size of individual crystals is not a key criterion, although larger aggregates are more desirable. ## Popular Localities The only source of bassoite specimens is the Big Creek mine in California. Material from this locality is highly valued by micromount collectors worldwide.

Care and storage

## Cleaning Bassoite specimens should not be cleaned mechanically or chemically due to their extreme fragility and small size. Any attempts at cleaning risk irreversible destruction of the crystals. If dust removal is necessary, it can be done very carefully using a photographic air blower, without touching the mineral surface. ## What to Avoid Avoid contact with water, chemicals, ultrasound, and sudden temperature changes. The crystals are brittle and sensitive to any vibrations and impacts. Do not expose specimens to direct sunlight, which may cause fading or degradation. ## Storage Bassoite specimens should be stored exclusively in specialized micromount boxes, which protect them from dust, moisture, and mechanical damage. Store in stable conditions, away from heat and light sources.

Sources

Read more