Adanite

Chemical formula: Pb<sup>2+</sup><sub>2</sub>(Te<sup>4+</sup>O<sub>3</sub>)(S<sup>6+</sup>O<sub>4</sub>)

Adanite is an extremely rare lead sulfate-tellurite, forming colorless, microscopic crystals, known from only one locality worldwide.

## Characteristics Adanite is a secondary lead mineral belonging to the sulfate-tellurite group. It forms very small, colorless, and transparent prismatic crystals, which usually occur in small, radial aggregates. Due to its microscopic size, individual crystals are difficult to observe without magnification. ## Physical Properties The mineral is characterized by a strong, adamantine luster. Its streak is white. Hardness and density have not yet been precisely determined due to the small amount of available research material. ## Colors and Varieties Adanite is colorless. No colored varieties are known. ## History and Name The mineral's name comes from the Adan mine (alternative name Aga mine) in Ibaraki Prefecture, Japan, which is its type locality. Adanite was officially approved as a new mineral by the International Mineralogical Association (IMA) in 2014. ## Uses Adanite has no industrial application. Due to its extreme rarity and microscopic size, it is solely an object of scientific interest and a valuable specimen in advanced systematic collections.

Properties

Luster
Adamantine
Streak
White
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Amateur identification of adanite is impossible. Due to the microscopic size of the crystals and their co-occurrence with other secondary lead minerals, its identification requires advanced analytical techniques such as X-ray microanalysis (EDS/WDS) and X-ray diffraction (XRD). ## Distinguishing from Similar Minerals Adanite can be confused with other colorless, secondary lead minerals with which it co-occurs, mainly anglesite and cerussite. Definitive differentiation is only possible based on chemical analysis, which will show the presence of tellurium. ## Crystal Forms Adanite forms small, elongated prismatic crystals, which often arrange themselves into small, radial or acicular aggregates on the surface of the host rock.

Geological environment

## Genesis Adanite is a secondary mineral, formed in the oxidation (weathering) zone of polymetallic deposits rich in tellurium. It forms as a result of the reaction of sulfate-containing solutions with primary minerals containing lead and tellurium. ## Mineral Associations This mineral occurs in direct association with other secondary lead minerals, such as anglesite (PbSO₄) and cerussite (PbCO₃). ## Localities The only confirmed locality of adanite in the world is its type locality - the Aga (Adan) mine in Naka City, Ibaraki Prefecture on Honshu Island, Japan.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of adanite specimens, which are exclusively micromounts, is assessed based on several criteria. The sharpness and degree of development of the microscopic crystals are most important. Specimens where crystals form rich, well-defined aggregates are more highly valued. The aesthetics of the substrate (matrix) and the presence of well-identified associated minerals are also important. ## Popular Localities The only source of adanite specimens is the Aga mine in Japan. Material from this locality is extremely difficult to obtain and goes almost exclusively to research institutions and the most advanced collectors specializing in rare minerals or micromounts.

Care and storage

## Cleaning Adanite specimens are almost exclusively micromounts. Any mechanical or chemical cleaning is absolutely inadvisable and risks irreversible destruction of the crystals. Only very careful dust removal with a soft brush or a rubber photographic blower is permissible. ## What to Avoid Avoid contact with all chemicals, ultrasonic cleaners, and any vibrations and shocks. The mineral is likely very soft and brittle. Do not touch it or expose it to temperature changes. ## Storage Specimens should be stored exclusively in specialized "micromount" boxes, which protect them from dust, mechanical damage, and shocks. Exposure should be away from sources of vibration.

Sources

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