Qiumingite
Chemical formula: Pb<sup>2+</sup><sub>3</sub>(Zn<sup>2+</sup><sub>2</sub>Fe<sup>3+</sup>)Sb<sup>5+</sup>P<sub>2</sub>O<sub>14</sub>
An extremely rare lead, zinc, iron, and antimony phosphate, forming microscopic, tabular, amber-colored crystals.
Description
## Characteristics Qiumingite is a very rare secondary mineral from the phosphate group, identified only in 2022. It occurs as very small, tabular or platy crystals, not exceeding 0.2 mm in size. These crystals often form rosette-like or irregular clusters and aggregates. Due to their microscopic size, specimens are mainly visible under magnification. ## Physical Properties The mineral is characterized by a Mohs hardness of 4. It has a high refractive index, which translates into a strong, adamantine luster. It is a dense mineral, with a density calculated from its chemical composition and crystal structure of 6.22 g/cm³. The crystals are transparent. ## Colors and Varieties Qiumingite has a characteristic, vivid color, ranging from amber-yellow to orange-yellow. The streak is pale yellow. No varieties have been distinguished. ## History and Name The mineral is named in honor of Professor Qiuming Zhang (b. 1963), a Chinese mineralogist from Peking University, for his contributions to mineral research. It was officially approved by the International Mineralogical Association (IMA) in 2022 under number IMA2022-094. The type locality, the first place of discovery, is the Qingchengzi ore field in China. ## Applications Due to its extreme rarity and microscopic crystal size, qiumingite has no commercial or industrial applications. It is solely an object of scientific research and a valuable acquisition for specialized collectors of systematic minerals.
Diagnostic features
## Identification Identification of qiumingite based on visual characteristics is impossible. Due to its microscopic size and resemblance to other yellow secondary minerals, its definitive identification requires advanced analytical techniques. Key diagnostic features include its unique chemical composition, confirmed by X-ray microanalysis (EDS/WDS), and a characteristic X-ray diffraction pattern (PXRD), which reflects its crystal structure. ## Distinguishing from Similar Minerals Visually, it may resemble other yellow or orange secondary minerals found in the oxidation zones of ore deposits, such as segnitite, mimetite, or pyromorphite. Without specialized chemical analysis, distinguishing it from these minerals is impossible. ## Crystal Forms Qiumingite forms thin, tabular crystals with a hexagonal outline. They typically occur as small, rosette-like or irregular clusters and aggregates growing on the host rock.
Geological environment
## Genesis Qiumingite is a secondary mineral that forms in the oxidation zone of metamorphosed, sedimentary polymetallic (Pb-Zn-Sb) deposits. It is formed by the weathering and alteration of primary ore minerals, such as galena, sphalerite, and jamesonite, in the presence of phosphorus-rich solutions. ## Mineral Associations This mineral occurs in association with other secondary and primary minerals. In the type locality, its co-occurrence with segnitite, ankerite, anglesite, and cerussite has been observed, as well as with remnants of primary ore: galena, sphalerite, and jamesonite. ## Localities The only confirmed locality for qiumingite in the world is its type locality – the Qingchengzi ore field, in Dandong Prefecture, Liaoning Province, China.
Rarity
Extremely rare
Collector aspects
## Quality Criteria The quality of qiumingite specimens, being a micromineral, is assessed according to specific criteria. Specimens with well-formed, sharp crystals of intense, amber color are most highly valued. Their arrangement on the rock matrix is also important – aesthetic, undamaged aggregates and rosettes are more desirable. The presence of other rare associated minerals increases the value of a specimen. ## Market Prices Due to its extreme rarity and recent discovery, qiumingite practically does not appear on the open collector's market. Specimens are mainly found in institutional collections and among specialized micromineral collectors. There is no established market or typical price ranges for this mineral. ## Popular Localities The only source of specimens is the type locality in China. Material from this location is extremely difficult to obtain.
Care and storage
## Cleaning Qiumingite specimens are typically microminerals, which are very delicate. Cleaning should be kept to an absolute minimum. For dust removal, it is best to use a photographic air blower or a very soft brush (e.g., squirrel hair). Avoid any contact with water and chemical agents, as its reactivity is unknown. ## What to Avoid The mineral is susceptible to mechanical damage, so avoid shocks, drops, and friction. Ultrasonic cleaners or any chemical solvents must not be used. Protect it from sudden temperature changes. ## Storage The safest way to store it is to keep the specimen in a specialized micromount box. This protects the fragile crystals from dust, moisture, and mechanical damage during handling.