Ertixiite

Chemical formula: Na<sub>2</sub>Si<sub>4</sub>O<sub>9</sub>

Ertixiite is a rare sodium silicate, forming colorless, tabular crystals with a hexagonal outline.

## Characteristics Ertixiite is a very rare mineral from the silicate group. It occurs in the form of small, colorless, hexagonal crystals with a tabular habit, reaching up to 0.3 mm in size. These crystals often form aggregates. Due to its small size and rarity, it is a mineral known primarily within the scientific community. ## Physical Properties Ertixiite crystals exhibit a vitreous luster. The mineral is transparent and colorless. Due to the very small size of the crystals, many physical properties, such as hardness or density, have not been thoroughly investigated or are calculated values. ## Colors and Varieties Ertixiite is colorless. No colored or commercial varieties are known. ## History and Name The mineral was first described in 1983 by J. Ruzhong, H. Zhaohui, Z. Huijun, P. Zhizhong, and Y. Haiming. Its name comes from the Ertix River (also known as Irtysh) in the Xinjiang Autonomous Region, China, where its type locality is situated. It was approved by the International Mineralogical Association (IMA) in 1982. ## Uses Ertixiite has no industrial or commercial applications. Its significance is purely scientific and collectible, although due to its microscopic nature, it is an object of interest for highly specialized collectors.

Properties

Luster
Vitreous
Streak
White
Density
2.44
Cleavage
Perfect on {0001}
Fracture
Uneven
Transparency
Transparent
Crystal system
Trigonal

Diagnostic features

## Identification Identification of ertixiite is possible almost exclusively using advanced laboratory methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS). Visually, on a micro scale, characteristic, colorless, hexagonal tablets can be observed. ## Distinguishing from Similar Minerals It can be confused with other colorless, hexagonal minerals occurring in similar environments, such as quartz or other rare silicates. Definitive differentiation requires analysis of chemical composition and crystal structure. ## Crystal Forms Ertixiite forms very small, thin, tabular crystals with a hexagonal outline. They occur individually or in small clusters and aggregates.

Geological environment

## Genesis Ertixiite forms in rare-earth-element-rich granitic pegmatites. It is a late-stage crystallization mineral in these specific, highly differentiated geological environments. ## Mineral Associations This mineral coexists with quartz, microcline, albite, aegirine, riebeckite, astrophyllite, elpidite, polylithionite, narsarsukite, and other rare pegmatite minerals. ## Localities The only confirmed and well-described locality for this mineral worldwide is its type locality – the Keketuohai (Koktokay) No. 3 granitic pegmatite in Fuyun County, Xinjiang Autonomous Region, China.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of an ertixiite specimen, being a "micromount" type mineral, is assessed based on the size and perfection of the crystals, their transparency, and their aesthetic arrangement on the rock matrix. The presence of associated minerals, which confirm the paragenesis, is also important. ## Popular Localities The only source of ertixiite specimens is its type locality in Keketuohai, China. Specimens from this location are the only ones available on the collector's market.

Care and storage

## Cleaning Due to the microscopic size and delicacy of the crystals, mechanical cleaning is not recommended and usually impossible. Specimens should be protected from dust in sealed containers. ## What to Avoid Avoid contact with chemicals, ultrasound, and extreme temperature changes. Specimens should not be touched to prevent damage to the delicate crystals. ## Storage The safest way to store ertixiite is to keep it in its original, sealed "micromount" box or another display container that protects against dust, shocks, and moisture.

Sources

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