Guite

Chemical formula: Co<sup>2+</sup>Co<sup>3+</sup><sub>2</sub>O<sub>4</sub>

Guite is a rare cobalt oxide from the spinel group, forming microscopic, octahedral crystals with a metallic luster.

## Characteristics Guite is a very rare mineral from the spinel group, being a cobalt oxide. It occurs as very small, most often microscopic, octahedral crystals, whose size rarely exceeds 0.1 mm. These crystals are usually embedded in calcite or other associated minerals. Due to its size, its visual features are difficult to observe without the use of specialized equipment, such as an electron microscope. ## Physical Properties Guite crystals exhibit a strong, metallic luster. The mineral is opaque. Its hardness and density have not been precisely measured due to the small size of the samples, but they are estimated based on the properties of other spinels. ## Colors and Varieties Guite has a black color and a black streak. No varieties have been distinguished. ## History and Name The mineral was approved by the International Mineralogical Association (IMA) in 2022. Its name honors Gu Xiang (also known as David Gu), a Chinese mineral collector and researcher who provided the sample for study. It was discovered in material from a polymetallic deposit in Yunnan Province, China. ## Uses Guite has no industrial application. Its significance is purely scientific and collectible, although due to the microscopic size of its crystals, it is primarily of interest to specialized collectors of microscopic minerals (so-called "micromounts").

Properties

Luster
Metallic
Streak
Black
Cleavage
None
Fracture
Uneven
Transparency
Opaque
Crystal system
Cubic

Diagnostic features

## Identification Identification of guite is only possible using advanced analytical methods, such as scanning electron microscopy (SEM) with chemical composition analysis (EDS) or X-ray diffraction (XRD). Under field conditions or in a typical collection, it is impossible to identify visually due to its microscopic size and resemblance to other black metallic minerals. ## Distinguishing from Similar Minerals Guite is visually indistinguishable from other black spinels, such as magnetite, chromite, or cochromite, with which it may co-occur. Definitive distinction requires chemical analysis confirming the dominance of cobalt in its composition. ## Crystal Forms It forms exclusively small, well-formed, single crystals with an octahedral habit. These crystals typically do not exceed 100 micrometers (0.1 mm) in size.

Geological environment

## Genesis Guite forms under hydrothermal conditions. In its type locality (Yunnan Province, China), it was found in calcite veins cutting through copper and cobalt deposits. Its crystallization is associated with processes occurring at low to medium temperatures. ## Mineral Associations This mineral co-occurs with calcite, cochromite, sphalerite, chalcopyrite, pyrite, bornite, carrollite, and quartz. ## Localities The only confirmed and described locality of guite occurrence in the world is the polymetallic copper and cobalt deposit in Yunnan Province, China.

Rarity

Extremely rare

For collectors

## Quality Criteria As a microscopic mineral, the collectible value of a specimen depends on several factors. The most important is the quality and size of the crystals themselves – the better-formed and larger (even if still microscopic) octahedra, the more valuable the specimen. The aesthetics of the rock matrix and the presence of rare associated minerals are also important. Precise documentation of origin and confirmation of mineral identification by analytical methods are of key importance. ## Popular Localities The only source of guite specimens is its type locality in Yunnan Province, China.

Care and storage

## Cleaning Due to the microscopic size of the crystals and their embedding in the rock matrix, mechanical cleaning is neither recommended nor possible. Specimens should be protected from dust. ## What to Avoid Contact with acids and other aggressive chemicals that could damage both the guite crystals themselves and associated minerals (e.g., calcite) should be avoided. Samples should be protected from shocks and friction. ## Storage Micromount specimens should be stored in specialized, sealed boxes to protect them from dust and mechanical damage. A label with precise locality information is crucial for the scientific value of the specimen.

External references

Sources

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