Liguowuite

Chemical formula: W<sup>6+</sup>O<sub>3</sub>

Liguowuite is a natural, hexagonal polymorph of tungsten(VI) oxide, forming microscopic, tabular crystals.

## Characteristics Liguowuite is a naturally occurring, hexagonal polymorph of tungsten(VI) oxide. It was discovered as extremely small, transparent, tabular crystals with a hexagonal outline, reaching sizes up to 15 micrometers in diameter and approximately 5 micrometers in thickness. It is observed as inclusions in other minerals, primarily diamond. Due to its microscopic size, its visual features are not visible to the naked eye. ## Physical Properties Liguowuite crystals are transparent and colorless, with a white streak. They exhibit a vitreous luster. Hardness and density have not been precisely measured due to sample size, but the calculated density is 7.43 g/cm³. ## History and Name The mineral was officially recognized by the International Mineralogical Association (IMA) in 2023 under number IMA2023-091. The name honors Liguo Gu (born 1963), a Chinese materials scientist, for his contributions to research on tungsten oxide. The discovery was made in the Luobusa diamond mine in Tibet. ## Applications Due to its extreme rarity and microscopic size, liguowuite has no industrial applications. It holds purely scientific significance and is an object of interest for specialized micromineral collectors.

Properties

Luster
Vitreous
Streak
White
Density
7.43
Cleavage
None
Fracture
Uneven
Transparency
Transparent
Crystal system
Hexagonal

Diagnostic features

## Identification Identification of liguowuite is possible only through advanced analytical techniques, such as Raman spectroscopy and electron backscatter diffraction (EBSD), due to its microscopic size and occurrence as inclusions. Visual identification is impossible. ## Distinguishing from Similar Minerals Liguowuite is a polymorph of tungstite (monoclinic WO₃) and tungstite (orthorhombic WO₃·H₂O). Distinguishing it from these requires crystal structure analysis. In practical collecting, there is no risk of confusion due to its unique environment of occurrence. ## Crystal Forms It forms hexagonal, tabular crystals with flat surfaces.

Geological environment

## Genesis Liguowuite forms under ultra-high pressure conditions in the Earth's deep mantle. It has been identified as an inclusion in diamond originating from peridotite, indicating its crystallization at depths exceeding 410 km. It is an ultra-high pressure (UHP) mineral. ## Mineral Associations This mineral was found as an inclusion in diamond. It coexists with other high-pressure minerals trapped in the same diamond, such as olivine, enstatite, pyrope, coesite, and the newly discovered maohokite. ## Localities The only confirmed locality of liguowuite in the world is the Luobusa ophiolite in the Tibetan Autonomous Region, China, where this mineral was found in alluvial diamonds.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a specimen is determined by the quality and size of the host diamond and the clarity and verifiability of the liguowuite inclusion itself. The most valuable specimens are those where the inclusion is clearly visible under a microscope and is accompanied by appropriate analytical documentation confirming its identity. ## Popular Localities The only source of specimens is the Luobusa diamond mine in Tibet, which makes them extremely rare and sought after by specialized collectors of high-pressure minerals and diamond inclusions.

Care and storage

## Cleaning Due to its mode of occurrence (microscopic inclusions in diamond), specimens do not require and are not amenable to cleaning. ## What to Avoid The host specimens (diamonds) are very durable, however, liguowuite itself as an inclusion is protected by the surrounding mineral. Any attempts to isolate the crystals should be avoided, as this would lead to their destruction. ## Storage Store in stable conditions, in specialized "micromount" boxes, protecting from dust and mechanical damage. Observation requires the use of a microscope.

Sources

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