Charleshatchettite

Chemical formula: CaNb⁵⁺₄O₁₀(OH)₂·₈H₂O

Charleshatchettite is an extremely rare niobium mineral, forming microscopic, bladed crystals with a pearly luster, discovered in Canada.

## Characteristics Charleshatchettite is a hydrated niobium and calcium oxide, occurring as extremely small, elongated crystals with dimensions not exceeding 200 micrometers in length and only a few micrometers in thickness. These crystals are colorless, transparent, and exhibit a characteristic pearly luster. They typically form small, radial aggregates or appear as single, bladed forms on the surface of other minerals. ## Physical Properties Due to the microscopic size of the crystals, most physical properties, such as hardness or density, have not been precisely measured, but only calculated based on crystallographic data. The calculated density is approximately 3.35 g/cm³. The luster is distinctly pearly, and the mineral is transparent. ## History and Name The mineral was officially recognized by the International Mineralogical Association (IMA) in 2015 under the number IMA2015-033. Its name honors Charles Hatchett (1765–1847), an English chemist who, in 1801, discovered the element niobium (then called columbium) while analyzing a mineral sample from the British Museum collection. ## Uses Charleshatchettite has no industrial applications. Its significance is purely scientific and collectible, as an extremely rare and recently discovered mineral species.

Properties

Mohs hardness: 4
Color: White
Luster: Pearlescent
Streak: White
Density: 2.878
Cleavage: Perfect on {010}
Transparency: Transparent,Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of charleshatchettite is impossible without advanced analytical equipment. Preliminary identification under a microscope is based on observing very small, colorless, bladed crystals with a strong pearly luster, often forming radial aggregates. Final confirmation requires chemical analysis (EDS) and structural analysis (X-ray diffraction). ## Distinguishing from similar minerals It can be confused with other microscopic secondary minerals of similar appearance, such as gypsum or other hydrated oxides. Differentiation is based on its unique chemical composition (presence of niobium and calcium) and characteristic crystal structure. ## Crystal forms Charleshatchettite forms strongly flattened, bladed or tabular crystals, elongated in one direction. These crystals group into small, radial or chaotic aggregates.

Geological environment

## Genesis Charleshatchettite is a secondary mineral, forming in the weathering (oxidation) zone of carbonatites. It forms as a result of low-temperature hydrothermal processes that lead to the alteration of earlier niobium minerals, such as pyrochlore. ## Mineral associations This mineral occurs in association with other niobium and zirconium minerals. In its type locality (Mont Saint-Hilaire), it was found in association with aegirine, microcline, quartz, natrolite, fluorite, zircon, pyrochlore, hematite, and goethite. ## Localities The only confirmed occurrence of charleshatchettite in the world is its type locality: Poudrette quarry, Mont Saint-Hilaire, in the Montérégie region of Quebec, Canada. This is one of the most famous mineralogical sites in the world, known for the occurrence of many rare and unique minerals.

Rarity

Extremely rare

For collectors

## Quality criteria The quality of a charleshatchettite specimen primarily depends on the abundance and size of crystal aggregates on the rock matrix. The most desirable specimens are those with clearly visible, well-formed, radial groups of crystals under the microscope. Due to the microscopic nature of the mineral, purity and color are not key factors. The aesthetics of the aggregate and the contrast with the substrate are important. ## Popular localities All known specimens come exclusively from the Poudrette quarry in Mont Saint-Hilaire, Canada. This is the sole source of this mineral, making every specimen, regardless of quality, an extremely valuable acquisition for specialized collectors of rare minerals and "micromounts."

Care and storage

## Cleaning Specimens containing charleshatchettite should be handled with utmost care. Due to the microscopic size and delicacy of the crystals, no mechanical or chemical cleaning is recommended. The safest method for dust removal is to use a gentle stream of compressed air from a safe distance. ## What to avoid Contact with water, chemicals, ultrasound, and any cleaning tools (brushes, cloths) must be strictly avoided. The crystals are extremely fragile and can be easily damaged or detached from the matrix. Sudden temperature changes should also be avoided. ## Storage Specimens should be stored under stable conditions, in enclosed "micromount" containers that protect them from dust, moisture, and mechanical damage. Display should only be done under a microscope.