Lishiite

Chemical formula: (Ca₂&#₉₇₄₄;)Sr₃(CO₃)₅

Lishiite is a very rare calcium and strontium carbonate, forming colorless, tabular crystals with a vitreous luster.

## Characteristics Lishiite is a mineral from the carbonate group, chemically classified as a calcium and strontium carbonate. It occurs as very small, colorless, tabular crystals, reaching sizes up to 0.2 mm. The crystals are transparent and characterized by a vitreous luster. Due to its extreme rarity and small crystal size, it is a mineral known primarily within the scientific community. ## Physical Properties Lishiite crystals exhibit a hardness of approximately 3 on the Mohs scale. The mineral has a density of 3.55 g/cm³. It is characterized by a vitreous luster and a white streak. It is transparent and colorless. ## History and Name The mineral's name comes from Professor Lishi Li of Peking University, in recognition of his contributions to mineralogy and petrology research. Lishiite was approved as a new mineral species by the International Mineralogical Association (IMA) in 2023 (IMA2023-080). The discovery was made at the Sijiaying iron ore mine in Hebei Province, China.

Properties

Mohs hardness: 3
Luster: Vitreous
Streak: White
Density: 3.55
Cleavage: Perfect on {0001}
Fracture: Uneven
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of lishiite is impossible without advanced laboratory techniques such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). Visually, at the occurrence site, one can observe small, colorless, tabular crystals with a vitreous luster, however, these features are not sufficient for certain identification. ## Distinguishing from Similar Minerals Lishiite can be confused with other colorless carbonates co-occurring in the same environment, such as calcite, aragonite, or strontianite. Differentiation requires analysis of chemical composition (high strontium and calcium content) and crystal structure. ## Crystal Forms The mineral forms thin, tabular crystals with a hexagonal outline, occurring individually or in small clusters on the surface of the host rock.

Geological environment

## Genesis Lishiite forms as a result of hydrothermal processes within an iron ore deposit. In its type locality (Sijiaying mine), it is a product of crystallization from hydrothermal solutions that interacted with strontium-rich rocks. ## Mineral Associations This mineral co-occurs with other hydrothermal minerals such as quartz, calcite, pyrite, fluorite, and also with other rare strontium carbonates. ## Localities The only confirmed locality of lishiite in the world is the Sijiaying iron ore mine, in Luan County, Hebei Province, China. This is its type locality.

Rarity

Extremely rare

For collectors

## Quality Criteria As a mineral of purely scientific importance and a "micromount" type, the only criteria for evaluation are the quality and size of the crystals and their association with the rock matrix. Any well-formed, identifiable crystal is considered a specimen of the highest value. ## Market Prices Lishiite is not traded on the collector's market. Specimens are found exclusively in scientific institutions and museums that participated in its study.

Care and storage

## Cleaning Due to its extreme rarity and fragility, lishiite specimens should not be cleaned mechanically or chemically. Any interventions should be left to specialists under laboratory conditions. ## What to Avoid Contact with acids, which rapidly decompose carbonates, should be avoided. The mineral is brittle, so any shocks and pressure should be avoided. Store away from moisture and extreme temperatures. ## Storage Lishiite specimens, typically in the form of microscopic crystals on a rock matrix, should be stored exclusively in specialized, padded "micromount" boxes. They should be protected from dust, vibrations, and direct light.

Sources

IMA Mineral List (CNMNC)