Davidsmithite

Chemical formula: (Ca,&#9744;)<sub>2</sub>Na<sub>6</sub>Al<sub>8</sub>Si<sub>8</sub>O<sub>32</sub>

An extremely rare sodium-calcium tectosilicate, forming colorless, hexagonal microcrystals in phonolites in Namibia.

## Characteristics Davidsmithite is a feldspathoid group mineral, a sodium-calcium aluminosilicate. It occurs as small, hexagonal, prismatic crystals, typically not exceeding 0.5 mm in length. They are colorless and transparent, with a vitreous luster. Due to its microscopic size, this mineral is almost exclusively available to specialized collectors and scientific institutions. ## Physical Properties The crystals exhibit a vitreous luster and are transparent. The calculated density is approximately 2.51 g/cm³. Hardness on the Mohs scale and other mechanical properties, such as cleavage or fracture, have not yet been definitively determined due to the small size of the samples. ## Colors and Varieties The mineral is colorless. No color or commercial varieties are distinguished. ## History and Name It was recognized as a new mineral species by the International Mineralogical Association (IMA) in 2006. Its name honors David G. Smith (1941–2015), a professor of geology at the University of Alberta in Canada, in recognition of his contributions to mineralogy and the development of microprobe techniques. ## Applications Davidsmithite has no industrial applications. Its significance is purely scientific and collectible within circles of micromineral specialists.

Properties

Luster
Vitreous
Streak
White
Density
2.51
Transparency
Transparent
Crystal system
Hexagonal

Diagnostic features

## Identification Identification of the mineral based on visual characteristics is impossible and requires specialized equipment. Final confirmation is only possible using advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis using an electron microprobe (EDS/WDS). Visually, it is a colorless, hexagonal microcrystal. ## Distinguishing from Similar Minerals At its locality, it can be confused with other colorless minerals, such as analcime, natrolite, or other zeolites, which form similar aggregates. Differentiation without specialized analysis is practically impossible. ## Crystal Forms It forms elongated, hexagonal, prismatic crystals, reaching up to 0.5 mm in size.

Geological environment

## Genesis It forms in the late, low-temperature stage of magma crystallization in miarolitic cavities in alkaline rocks, specifically in phonolites. ## Mineral Associations It co-occurs with aegirine, analcime, natrolite, and microcline. ## Localities The only known locality in the world (type locality) is the Aris phonolite quarries, near Windhoek in the Khomas Region, Namibia.

Rarity

Extremely rare

For collectors

## Quality Criteria For micromineral collectors, the sharpness and good development of the crystal, its transparency, and attractive placement on the rock matrix are paramount. A well-defined, isolated crystal is more desirable than tangled aggregates. ## Market Prices Due to its extreme rarity, davidsmithite practically does not appear on the open market. Its value is difficult to estimate and is primarily scientific and sentimental for specialized collectors. ## Popular Localities The only source of specimens is the Aris quarries in Namibia, known worldwide for the occurrence of many rare minerals crystallizing in alkaline environments.

Care and storage

## Cleaning Micromineral specimens, such as davidsmithite, generally do not require cleaning. If necessary, compressed air (from a safe distance and at low pressure) can be used to remove dust. Contact with water and chemicals should be strictly avoided. ## What to Avoid Due to their microscopic size and rarity, crystals are extremely sensitive to mechanical damage. Avoid shocks, ultrasonic cleaning, sudden temperature changes, and any chemical solvents. ## Storage The safest form of storage is a specialized "micromount" box, which protects the specimen from dust and mechanical damage. Store in a dry place with stable temperature, away from direct sunlight.

External references

Sources

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