Kingsmountite

Chemical formula: Ca₃Mn₂+Fe₂+Al₄(PO₄)₆(OH)₄·₁₂H₂O

Kingsmountite is a very rare phosphate mineral forming white, radial aggregates, discovered in the Kingsmount mine in Canada.

## Characteristics Kingsmountite is a hydrated calcium, manganese, iron, and aluminum phosphate. It forms characteristic, spherical or hemispherical aggregates with a radial structure, composed of very fine, acicular or lamellar crystals. Individual crystals are usually too small to be seen with the naked eye. These aggregates typically have a white color and a silky luster. ## Physical Properties This mineral is relatively soft, with a Mohs hardness of approximately 3. It has a silky luster, and its crystals are transparent to translucent. The density of kingsmountite is approximately 2.55 g/cm³. ## Colors and Varieties Kingsmountite is usually white, sometimes with a slight creamy or yellowish tint. No varieties have been distinguished. ## History and Name The mineral's name comes from its discovery locality – the Kingsmount mine in the Pakenham area of Lanark County, Ontario, Canada. It was described and approved as a new mineral species in 1980 by a team of mineralogists: Pete J. Dunn, Donald R. Peacor, B. Darko Sturman, and Julie A. Norberg. ## Uses Kingsmountite has no industrial application. It is solely a mineral of scientific and collector's interest, sought after for its rarity and aesthetic forms of occurrence.

Properties

Mohs hardness: 3
Luster: Silky
Streak: White
Density: 2.55
Cleavage: Perfect on {010}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Kingsmountite can be identified by its characteristic white, radial or spherical aggregates with a silky luster. It occurs in a specific geological environment – in granitic pegmatites. ## Distinguishing from Similar Minerals It can be confused with other white phosphate minerals forming radial aggregates, such as wavellite or wardite. Distinguishing it requires advanced research methods, such as chemical analysis (EDS) or X-ray diffraction (XRD), due to its unique chemical composition. ## Crystal Forms Kingsmountite crystals are elongated along the [001] axis and flattened parallel to {010}. They form radial, spherical, or hemispherical aggregates, as well as fibrous masses.

Geological environment

## Genesis Kingsmountite is a secondary mineral, forming in the late stages of crystallization of complex granitic pegmatites. It forms as a result of hydrothermal processes or the weathering of primary phosphate minerals in the presence of solutions rich in calcium, manganese, iron, and aluminum. ## Mineral Associations This mineral co-occurs with other pegmatitic phosphates. At the type locality (Kingsmount mine), it was found in association with eosphorite, cyrilite, rockbridgeite, strengite, whitmoreite, jahnsite, goethite, quartz, and microcline. ## Localities The most important and best-documented occurrence of kingsmountite is its type locality – the Kingsmount mine in Ontario, Canada. This is the only locality from which well-formed, classic specimens of this mineral originate.

Rarity

Very rare

For collectors

## Quality Criteria The most prized kingsmountite specimens are those that exhibit well-formed, spherical aggregates with a distinct radial structure and silky luster. Contrast with the rock matrix and the absence of damage to the delicate fibers are important. The size of the aggregates also affects value, with specimens featuring spheres exceeding one centimeter in diameter being rare. ## Popular Localities The only source of valuable collector's specimens is the Kingsmount mine in Ontario, Canada. Material from this locality is considered exemplary for this species.

Care and storage

## Cleaning Kingsmountite specimens should be cleaned very carefully, using a soft brush to remove dust. Due to its softness and delicate structure, avoid washing with water, which could damage the radial aggregates. ## What to Avoid Avoid contact with all chemicals, including acids and detergents. The mineral is sensitive to high temperatures, which can cause dehydration and structural damage. It should also be protected from shocks and impacts. ## Storage Collector's specimens of kingsmountite are best stored in closed, padded boxes or display cases to protect them from dust, mechanical damage, and sudden changes in humidity.

Sources

IMA Mineral List (CNMNC)