Krautite

Chemical formula: Mn₂+(As₅+O₃OH)·H₂O

A rare manganese arsenate with a characteristic pink color, forming radiating aggregates or clusters of small, bladed crystals.

## Characteristics Krautyte is a hydrated manganese arsenate that typically occurs as small, bladed or acicular crystals clustered into radiating, spherulitic aggregates. It also forms granular and massive aggregates. Its most characteristic feature is an intense, pink to reddish-pink color, which can fade when exposed to light. ## Physical Properties Krautyte crystals are usually very small, rarely exceeding a few millimeters in length. The mineral exhibits a vitreous to pearly luster, particularly noticeable on cleavage surfaces. It is translucent to opaque. Its Mohs hardness is approximately 4. ## Colors and Varieties The dominant and virtually only color found in krautyte is pink in various shades – from pale pink, through intense, almost neon pink, to reddish pink. No color or commercial varieties are distinguished. ## History and Name The mineral was first described in 1975 by François Permingeat, Hélène Hélène, and Jean-Claude Pierrot. The name honors François Kraut (1907-1983), a French mineralogist and curator of mineral collections at the National Museum of Natural History in Paris, for his contributions to the study of arsenates from mines in Romania. ## Uses Krautyte has no industrial applications. It is solely a mineral of scientific and collector's interest, valued for its rarity and intense color.

Properties

Mohs hardness: 4
Luster: Vitreous to Pearly
Streak: Pale pink
Density: 3.87
Cleavage: Perfect on {010}
Fracture: Uneven
Transparency: Translucent to Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Key diagnostic features of krautyte include its intense pink color, habit in the form of radiating aggregates composed of bladed crystals, and perfect cleavage in one direction. The pearly luster on cleavage planes is also characteristic. ## Distinguishing from Similar Minerals Krautyte is sometimes confused with rhodochrosite, which is also pink and associated with manganese. However, rhodochrosite is a carbonate, reacts with hydrochloric acid, has a higher hardness (3.5-4 vs 4 for krautyte), and typically forms rhombohedral crystals or banded aggregates, not radiating bladed aggregates. Erythrite has a similar color and habit, but it is a cobalt arsenate and occurs in different mineral associations. ## Crystal Forms Krautyte crystals are elongated, bladed or acicular, flattened parallel to the direction of perfect cleavage. They most often form fan-shaped or radiating aggregates, rosettes, and spherulitic clusters. Less commonly, they occur as granular aggregates.

Geological environment

## Genesis Krautyte is a secondary mineral formed in the oxidation zones of hydrothermal ore deposits rich in manganese and arsenic. It forms as a result of the alteration of earlier manganese minerals (like rhodochrosite) and arsenic minerals (like arsenopyrite) under low-temperature and low-pressure conditions. ## Mineral Associations This mineral often co-occurs with other manganese arsenates, such as brandtite, sarkinite, allactite, as well as with rhodochrosite, hausmannite, pyrophanite, galena, sphalerite, and quartz. ## Localities The type locality, where krautyte was first identified, is the Săcărâmb mine (formerly Nagyág) in Romania. Other known occurrences include the Sterling Hill mine in New Jersey (USA), Broken Hill in New South Wales (Australia), and mines in the Vatra Dornei region in Romania. Occurrences have also been reported in Japan (Gozaisho mine) and Switzerland (Val d'Anniviers).

Rarity

Rare

For collectors

## Quality Criteria The most sought-after krautyte specimens by collectors are characterized by an intense, saturated pink color that has not faded. Well-formed, radiating aggregates and spherulites with a distinct structure, set on a contrasting rock matrix, are highly valued. The size of the aggregates is also important – the larger and more complete, the more valuable the specimen. The purity of the specimen, i.e., the absence of mechanical damage and undesirable coatings, is crucial. ## Popular Localities The historical Săcărâmb locality in Romania is considered the source of the best quality krautyte specimens. Classic, intensely colored, radiating aggregates originate from there. Specimens from Broken Hill in Australia are also prized, although they often have a slightly different habit.

Care and storage

## Cleaning Krautyte specimens should be cleaned with the utmost care. Due to its softness and perfect cleavage, only gentle brushing with a soft brush is recommended. The use of water is inadvisable, as the mineral is hydrated and may undergo changes. Ultrasonic cleaners should be avoided. ## What to Avoid Krautyte is sensitive to sunlight, under the influence of which its intense pink color may fade over time. Exposure to high temperatures, which can lead to dehydration and destruction of crystals, should be avoided. The mineral is also sensitive to chemicals, especially acids. Due to its arsenic content, inhaling dust should be avoided, and hands should be washed after contact with the specimen. ## Storage Specimens should be stored in a dark and dry place to protect them from light and moisture. It is best to place them in a closed, padded collector's box, away from harder minerals that could scratch them. Due to its fragility, handling of the specimen should be minimized.

Sources

IMA Mineral List (CNMNC)