Manganonewberyite

Chemical formula: Mn<sup>2+</sup>(PO<sub>3</sub>OH)(H<sub>2</sub>O)<sub>3</sub>

Manganonewberyite is a rare, hydrated manganese phosphate, forming tabular crystals with a vitreous luster, found in granitic pegmatites.

## Characteristics Manganonewberyite is a hydrated manganese phosphate, being the manganese analogue of newberyite. It forms characteristic, tabular crystals, often grouped into radiating or fan-shaped aggregates. It usually occurs as small crystals, rarely exceeding a few millimeters in length. It is a brittle mineral. ## Physical Properties Manganonewberyite's hardness on the Mohs scale is 3 to 3.5, making it a relatively soft mineral. It has a vitreous luster, and on cleavage surfaces, it may exhibit a pearly luster. It is transparent to translucent. Its density is approximately 2.55 g/cm³. ## Colors and Varieties This mineral is most often colorless, white, pale pink, or light brown. A delicate, pink coloration, if present, is typical and associated with the presence of manganese in its structure. No named color varieties or commercial varieties are distinguished. ## History and Name The name manganonewberyite, given in 1981 by Donald R. Peacor, Pete J. Dunn, and William B. Simmons, refers to its chemical composition (dominant manganese) and structural similarity to the mineral newberyite. It was discovered and described based on specimens from the Tip Top mine in Custer County, South Dakota, USA. ## Applications Manganonewberyite has no industrial application. It is valued solely as a collector's mineral, sought after for its rarity, attractive crystal forms, and occurrence in paragenesis with other rare phosphates.

Properties

Mohs hardness
3-3.5
Luster
Vitreous, Pearly
Streak
White
Density
2.55
Cleavage
Good on {010}
Fracture
Uneven
Transparency
Transparent to Translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Features facilitating identification include the tabular habit of crystals, often forming radiating aggregates, pale pink color, vitreous or pearly luster, and occurrence in a pegmatitic environment. Good cleavage in one direction is also a helpful indicator. ## Distinguishing from Similar Minerals Manganonewberyite can be confused with its magnesium analogue, newberyite, which, however, is usually colorless or white and does not show a pink tint. From other secondary pegmatitic phosphates, such as hureaulite, it is distinguished by its crystal habit (hureaulite forms prismatic or columnar crystals) and usually lighter color. ## Crystal Forms Manganonewberyite crystals are typically thin- or thick-tabular, with a rectangular or hexagonal outline. They most often occur in the form of radiating or fan-shaped aggregates, growing on other minerals or filling small fissures in the rock.

Geological environment

## Genesis Manganonewberyite is a secondary mineral. It forms as a result of low-temperature hydrothermal processes or weathering in granitic pegmatites. It forms from the alteration of primary, manganese-rich phosphate minerals, mainly lithiophilite and triplite. ## Mineral Associations It most often co-occurs with other phosphates, such as lithiophilite, triplite, hureaulite, reddingite, eosphorite, vivianite, as well as with quartz, microcline, and muscovite. ## Localities The most important localities worldwide, from which well-formed specimens originate, are the Tip Top mine in South Dakota and Palermo No. 1 Mine in New Hampshire (USA), as well as the Hagendorf-Süd pegmatite in Bavaria (Germany). Occurrences have also been reported in Portugal and Australia.

Rarity

Rare

For collectors

## Quality Criteria The most highly valued specimens are those with sharply terminated, transparent crystals of a distinct pink color, forming aesthetic, radiating aggregates. The contrasting rock matrix and paragenesis with other rare and well-formed phosphate minerals are also of great importance. ## Popular Localities The type locality – the Tip Top mine in South Dakota (USA) – and the Hagendorf-Süd pegmatite in Germany are considered classic and provide the best collectible specimens. Specimens from these locations are most sought after by collectors specializing in phosphates.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using a soft brush and distilled water. Due to its low hardness and brittleness, strong friction should be avoided. Ultrasonic cleaners are not recommended, as they can damage delicate crystals. ## What to Avoid The mineral is sensitive to acids. As a hydrated mineral, it is susceptible to dehydration at elevated temperatures, which can lead to its permanent damage or transformation into another mineral. It should be protected from high temperatures and sudden changes in temperature. ## Storage It is recommended to store specimens in closed boxes or display cases to protect them from dust and mechanical damage. Due to its brittleness and good cleavage, it should be avoided to place it in direct contact with harder minerals.

Sources

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