Whiteite-(CaMnMn)
Chemical formula: CaMn<sup>2+</sup>Mn<sup>2+</sup><sub>2</sub>Al<sub>2</sub>[PO<sub>4</sub>]<sub>4</sub>(OH)<sub>2</sub>·8H<sub>2</sub>O
A rare phosphate mineral from the whiteite group, forming small, tabular crystals with a vitreous luster, prized by collectors of rare minerals.
Properties
- Mohs hardness
- 3.5
- Luster
- Vitreous
- Streak
- White
- Density
- 2.89 - 2.96
- Cleavage
- Perfect on {001}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Whiteite-(CaMnMn) is identified by its characteristic crystal form (small, tabular), yellowish color, vitreous luster, and occurrence environment – granitic pegmatites. However, definitive identification requires advanced analytical methods, such as chemical analysis (EDS) or X-ray diffraction (XRD), due to its similarity to other phosphate minerals. ## Distinguishing from Similar Minerals This mineral can be confused with other members of the whiteite group, such as whiteite-(CaFeMg) or whiteite-(MnFeMg), from which distinction is practically only possible through chemical analysis. It may also resemble other small, yellowish phosphates found in pegmatites, e.g., some minerals from the apatite group or wardite. ## Crystal Forms Crystals are most often tabular, flattened parallel to the {001} plane, with a pseudohexagonal or square outline. They form fan-shaped, radial, or rosette-like aggregates on the surface of other minerals, mainly in vugs and rock fissures.
Geological environment
## Genesis Whiteite-(CaMnMn) is a secondary mineral, forming in the late stages of crystallization of complex granitic pegmatites, rich in phosphorus. It forms as a result of hydrothermal processes or through the alteration of earlier phosphate minerals, such as triplite or lithiophilite. ## Mineral Associations It most commonly co-occurs with other phosphate minerals, such as eosphorite, rockbridgeite, strengite, wardite, as well as with quartz, microcline, muscovite, and albite. ## Localities The most important and classic occurrences of this mineral are in the United States, including the Palermo No. 1 and Fletcher mines in the Groton area of New Hampshire, and the Tip Top mine in Custer County, South Dakota. It also occurs in Brazil in the state of Minas Gerais.
Rarity
Very rare
For collectors
## Quality Criteria Specimens with sharp, well-formed crystals forming aesthetic, rosette-like aggregates are most valued by collectors. The intensity and purity of the color are important – specimens with a vibrant, yellow color are preferred. Contrast with the matrix mineral also enhances visual and collector value. Due to their small size, the quality of the crystals themselves, rather than the size of the entire specimen, is key. ## Popular Localities Specimens from classic US localities, such as the Tip Top mine in South Dakota or the mines in New Hampshire, are particularly sought after by collectors due to their historical significance and material quality.
Care and storage
## Cleaning Specimens should be cleaned very carefully, using a soft brush to remove dust. Due to its brittleness and perfect cleavage, ultrasonic cleaners and strong water jets should be avoided. If liquid is necessary, distilled water is recommended. ## What to Avoid Avoid contact with acids and other chemicals that can damage the mineral's surface. The mineral is sensitive to impacts and scratches. It should not be heated or exposed to sudden temperature changes. ## Storage Whiteite-(CaMnMn) specimens should be stored in separate, padded collector boxes to prevent abrasions and mechanical damage. Due to the small size of the crystals, "micromount" type boxes are ideal. They should be protected from dust and moisture.