Artsmithite

Chemical formula: Hg<sup>1+</sup><sub>4</sub>Al(PO<sub>4</sub>)<sub>1.74</sub>(OH)<sub>1.78</sub>

Artsmithite is an extremely rare aluminum and mercury phosphate, forming microscopic crystals of an intense canary-yellow color.

## Characteristics Artsmithite is a secondary mercury mineral, occurring as microscopic coatings and aggregates. It forms extremely small, tabular crystals, rarely exceeding 0.1 mm, which form druses and aggregates up to 0.5 mm. Its most characteristic feature is its intense, canary-yellow color. Specimens have a strong, adamantine luster, which gives them a vibrant appearance despite their small size. ## Physical Properties This mineral is translucent. Due to the presence of mercury, it has a very high density, calculated at 7.33 g/cm³. Hardness on the Mohs scale has not been determined due to the microscopic size of the crystals. No cleavage has been observed. ## Colors and Varieties Artsmithite occurs exclusively in one characteristic color – canary-yellow. No color varieties or commercial varieties are known. ## History and Name The mineral is named in honor of Arthur “Art” Smith (1916–1997), a Californian mineral collector who found the first samples containing this mineral. It was described and approved as a new species in 2003. The type locality and only known occurrence is the Clear Creek Claim area in San Benito County, California, USA. ## Applications Due to its extreme rarity and microscopic size, artsmithite has no industrial applications. It is solely an object of scientific research and a valuable acquisition for specialized collectors of rare minerals and microminerals.

Properties

Luster
Adamantine
Streak
Pale yellow
Density
7.33
Cleavage
None
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Key diagnostic features of artsmithite include its unique canary-yellow color, very strong adamantine luster, high density, and occurrence as microscopic coatings. Final confirmation is its mineral association and locality, as it is known from only one place in the world. ## Distinguishing from Similar Minerals It can be confused with other secondary yellow minerals. However, artsmithite is distinguished by its co-occurrence with other mercury minerals, such as cinnabar or native mercury, in the specific geological environment of siliceous-carbonate rocks. Its extreme rarity and restriction to the type locality are decisive distinguishing factors. ## Crystal Forms Artsmithite forms microscopic, tabular crystals, most commonly occurring as crusts, coatings, and small, radial aggregates on the host rock.

Geological environment

## Genesis Artsmithite is a secondary mineral, formed under low-temperature hydrothermal conditions. It forms as a result of the alteration of other, earlier mercury minerals within siliceous-carbonate rocks, which constitute the host rock for mercury deposits in the New Idria region. ## Mineral Associations This mineral occurs in close association with other mercury minerals. The most common associations include native mercury, cinnabar, edoylerite, and watiersite. ## Localities The only confirmed and described locality for artsmithite in the world is the Clear Creek Claim in the New Idria district, San Benito County, California, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria For a micromineral like artsmithite, collector value is determined by the richness and extent of the coating on the host rock. Specimens with clearly formed, though still microscopic, crystalline aggregates are highly prized. The aesthetic composition with associated minerals is also very important, especially with clearly visible droplets of native mercury or red cinnabar crystals. ## Popular Localities As this mineral is known from only one locality, all collector specimens originate from the Clear Creek Claim in California. This is a classic locality for many rare mercury minerals, making samples from there particularly sought after by specialists.

Care and storage

## Cleaning Cleaning artsmithite specimens is highly inadvisable due to their toxicity and fragility. If dust removal is necessary, a stream of compressed air can be used from a safe distance. Contact with water and chemical agents must be strictly avoided. ## What to Avoid Artsmithite is a mercury mineral and is toxic. Direct skin contact and inhalation of dust that might arise during handling should be avoided. It must not be heated, as this can release toxic mercury vapors. It should be protected from moisture, acids, and other chemicals. ## Storage Specimens should be stored in a tightly sealed, transparent container (e.g., a micromount box), with a clear label warning of toxicity. It should be kept in a dry place, away from heat sources and direct sunlight, and separate from other minerals to prevent potential contamination.

Sources

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