Whiteite-(MnMnMn)
Chemical formula: Mn²⁺Mn²⁺Mn²⁺₂Al₂(PO₄)₄(OH)₂·8H₂O
A rare phosphate from the whiteite group, forming small, tabular crystals of pale yellow to brown color, found in granitic pegmatites.
Properties
- Mohs hardness
- 4
- Color
- colourless to very pale brown
- Luster
- Vitreous
- Streak
- white
- Density
- 2.82
- Cleavage
- poor cleavage on {001}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identification of whiteite-(MnMnMn) under amateur conditions is practically impossible and requires advanced analytical methods, such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). Preliminary identification is based on the characteristic habit of thin, tabular crystals forming rosette-like aggregates, color, and co-occurrence with other rare phosphates in pegmatites. ## Distinguishing from similar minerals This mineral is visually indistinguishable from other members of the whiteite group, such as whiteite-(CaMnMg) or whiteite-(CaFeMg), as well as many other fine-grained, yellow and brown phosphates. Certain differentiation is possible only based on chemical analysis. ## Crystal forms Crystals are thin, tabular, flattened parallel to {010} and elongated along the [001] axis. They usually form fan-shaped or rosette-like aggregates, in which individual crystals radiate outwards.
Geological environment
## Genesis Whiteite-(MnMnMn) is a secondary mineral, formed in complex granitic pegmatites. It forms as a result of hydrothermal or metasomatic processes acting on earlier, primary phosphate minerals, such as triplite. ## Mineral associations This mineral co-occurs with other phosphates, such as dickinsonite, fillowite, triplite, eosphorite, strengite, rockbridgeite, as well as quartz and albite. ## Localities The most important and typical occurrence (locus typicus) of this mineral is the Palermo No. 1 quarry in Groton, Grafton County, New Hampshire, USA. This is the only confirmed and thoroughly described locality of this mineral in the world.
Rarity
Very rare
For collectors
## Quality criteria The collecting appeal of whiteite-(MnMnMn) specimens primarily depends on their scientific value and rarity. The most prized specimens are those with well-formed, sharp crystals forming aesthetic, rosette-like aggregates. Association with other rare minerals from the given locality is also important. Due to the microscopic size of the crystals, their transparency and color intensity are of secondary importance. ## Popular localities The only source of collector specimens is the historical type locality – the Palermo No. 1 quarry in New Hampshire, USA. Material from this location is extremely rare and sought after by specialized collectors of rare minerals and micromounts.
Care and storage
## Cleaning Specimens should be cleaned only very carefully, using a soft brush to remove dust. Due to potential reactivity and the small size of the crystals, contact with water, and especially with chemical cleaning agents, should be avoided. ## What to avoid Avoid ultrasonic cleaners, all acids, and detergents. The mineral is relatively soft and brittle, so it must be protected from impacts and scratches. It should not be heated or exposed to sudden temperature changes. ## Storage It is recommended to store specimens in stable conditions, in closed collector boxes that protect against dust, moisture, and mechanical damage. Due to the small size of the crystals, boxes with a magnifying glass in the lid are ideal.