Daomanite

Chemical formula: CuPtAsS₂

Daomanite is a rare copper, platinum, and arsenic sulfide, forming tiny, tabular crystals with a metallic luster and steel-gray color.

## Characteristics Daomanite is a rare and complex mineral from the sulfosalt group, composed of copper, platinum, arsenic, and sulfur. It occurs as very small, tabular or bladed crystals, rarely exceeding 1 mm in length. It typically forms granular aggregates or occurs as inclusions in other minerals. Its characteristic features include a metallic luster and a steel-gray color, often with a subtle, yellowish tint. ## Physical Properties This mineral is relatively soft, with a hardness of 3.5 on the Mohs scale. It is opaque and exhibits a strong, metallic luster. Its density has not been precisely determined. It shows four cleavage directions of varying perfection, which is an unusual feature. ## Colors and Varieties Daomanite is color-uniform and occurs in steel-gray shades, sometimes with a visible yellowish or creamy tint. No color or commercial varieties are distinguished. ## History and Name The mineral's name comes from the Chinese words "dao" (knife) and "man" (full), which refers to its chemical composition rich in platinum (Pt) and arsenic (As), as well as the tabular shape of its crystals. It was first described in 1974 based on specimens found at two localities in Hebei Province, China: the Tiema-Habaqin complex (Luanping County) and the Sandao village area (Fengning County). ## Uses Due to its extreme rarity and microscopic crystal size, daomanite has no industrial applications. It is solely an object of scientific interest and a collector's item for specialized collectors of rare minerals.

Properties

Mohs hardness
3.5
Luster
Metallic
Density
0
Cleavage
Four sets (from best to least perfect) {100} {010} {001} {110}
Fracture
Irregular/Uneven,Step-Like
Transparency
Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Amateur identification of daomanite is practically impossible due to its microscopic size and resemblance to other sulfides and sulfosalts. Definitive identification requires advanced analytical methods, such as reflected light ore microscopy and chemical composition analysis (e.g., using an electron microprobe). ## Distinguishing from Similar Minerals Daomanite can be confused with many other metallic minerals found in similar parageneses, such as bornite, sperrylite, or other platinum group element sulfides. Differentiation is based on chemical composition analysis and crystallographic data. The presence of copper, platinum, and arsenic in its structure is characteristic. ## Crystal Forms Daomanite crystallizes as very small, thin tablets or blades, often elongated. Crystals rarely occur individually, usually forming irregular aggregates, granular masses, or inclusions within other minerals, mainly copper and iron sulfides.

Geological environment

## Genesis Daomanite is a hydrothermal mineral, associated with copper and nickel deposits in ultramafic and mafic rocks, such as peridotites and gabbros. It forms as a result of crystallization from solutions rich in sulfur, arsenic, and metals, including platinum and copper, at relatively low temperatures. ## Mineral Associations This mineral co-occurs with other sulfides and arsenides. In the type locality, it was found in association with bornite, chalcopyrite, pyrrhotite, pentlandite, sperrylite, platarsite, as well as native platinum and gold. ## Localities Daomanite is an extremely rare mineral, known from only a few locations worldwide. Besides the two type localities in Hebei Province, China, its occurrence has also been reported in the Oktyabrskoye nickel-copper deposit in Siberia, Russia, and in the Bushveld Complex in the Republic of South Africa.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a daomanite specimen is determined almost exclusively by its scientific and documentary value. Since the crystals are microscopic, the most important factor is the certainty of mineral identification, confirmed by analyses. Specimens where daomanite is relatively abundant or forms more distinct aggregates are valued, as are those from well-documented type localities. ## Popular Localities The most "classic" specimens, though still extremely rare, come from the original localities in Hebei Province, China. Any specimen with confirmed daomanite, regardless of locality, is considered unique and valuable to specialized collectors.

Care and storage

## Cleaning Daomanite specimens, due to their microscopic size and delicacy, are practically not subject to cleaning. Any attempts at mechanical removal of contaminants can easily damage or destroy the crystals. If cleaning is absolutely necessary, compressed air can be carefully used to blow away dust. ## What to Avoid Avoid contact with any chemicals, including acids and bases, which can react with sulfides. Specimens should also be protected from moisture, which can lead to oxidation and degradation of the mineral. Avoid ultrasonics and steam cleaning. ## Storage Specimens containing daomanite should be stored under stable conditions, in a dry environment. The best solution is to place them in sealed, airtight "micromount" boxes, which protect against dust, moisture, and mechanical damage.

External references

Sources

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