Chudobaite

Chemical formula: Mg₅(As⁵⁺O₄)₂(As⁵⁺O₃OH)₂·₁₀H₂O

Chudobaite is a rare, hydrated magnesium arsenate, forming small, tabular crystals of pink, white, or colorless hue.

## Characteristics Chudobaite is a rare, hydrated magnesium arsenate belonging to the ondrušite group. It occurs as small, tabular or bladed crystals, often aggregated into radial or fan-shaped clusters. Specimens are usually small, rarely exceeding a few millimeters in length. This mineral is valued by collectors specializing in rare species, especially from the Tsumeb mine. ## Physical Properties Chudobaite is a relatively soft mineral, with a hardness of 2.5-3 on the Mohs scale. Its density is approximately 2.94 g/cm³. Crystals are transparent and exhibit a vitreous luster. It has very good cleavage in one direction and good cleavage in another, making it brittle and delicate. ## Colors and Varieties The most common specimens are pink, ranging from pale pink to more intense shades. It also occurs in white variants and as completely colorless crystals. There are no named varieties of this mineral. ## History and Name The mineral was described in 1960 by Hugo Strunz. The name "chudobaite" honors Karl F. Chudoba (1898-1976), an Austrian mineralogist and professor at the University of Göttingen, for his contributions to mineralogy. The type locality, from which the first described material originated, is the famous Tsumeb mine in Namibia. ## Uses Chudobaite has no industrial applications. Its significance is purely scientific and collectible.

Properties

Mohs hardness: 2.5-3
Luster: Vitreous
Streak: White
Density: 2.94
Cleavage: {010} very good. {100} good.
Fracture: Uneven
Transparency: Transparent
Crystal system: Triclinic

Diagnostic features

## Identification Chudobaite is recognized by its characteristic habit of tabular or bladed crystals, often forming radial aggregates. Pink color, vitreous luster, and occurrence in paragenesis with other arsenates from Tsumeb are key indicators. Low hardness and excellent cleavage also aid in identification. ## Distinguishing from Similar Minerals It can be confused with other pink arsenates, such as erythrite or köttigite. Erythrite has a more intense, carmine color and forms acicular crystals. Köttigite also forms acicular or hair-like aggregates. Accurate differentiation often requires advanced analytical methods, such as chemical analysis (EDS) or X-ray diffraction (XRD). ## Crystal Forms Chudobaite crystals are typically tabular, flattened parallel to {010}, or have an elongated bladed form. They often occur as radial, fan-shaped, or nearly spherical aggregates, as well as rosetted clusters on the host rock.

Geological environment

## Genesis Chudobaite is a secondary mineral formed in the oxidation zones (gossans) of polymetallic ore deposits rich in arsenic. It forms as a result of the weathering of primary arsenic minerals in the presence of magnesium-rich solutions. ## Mineral Associations At the type locality (Tsumeb), it co-occurs with other rare arsenates, such as prosopite, magnesite, quartz, tennantite, germanite, galena, stranskiite, ludlockite, and schneiderhöhnite. ## Localities The most important and historically first occurrence of chudobaite is the Tsumeb mine in Namibia, from which the best known specimens originate. This is practically the only locality from which this mineral has been obtained in quantities of collector significance.

Rarity

Very rare

For collectors

## Quality Criteria The most prized chudobaite specimens are characterized by well-formed, sharp crystals with an intense, pink color. Aesthetic, radial aggregates on a contrasting rock matrix are highly valued. The size of crystals and aggregates is a key factor influencing value, as is the absence of damage and the specimen's purity. ## Popular Localities The only known and valued locality by collectors is the Tsumeb mine in Namibia. Specimens from this locality are considered classic and serve as a benchmark for this mineral.

Care and storage

## Cleaning Chudobaite specimens should be cleaned with utmost care due to their brittleness and softness. For dust removal, it is best to use a soft brush or compressed air from a safe distance. If wet cleaning is necessary, use only distilled water and a very delicate brush, avoiding strong rubbing. ## What to Avoid Avoid contact with acids and other chemicals that can damage the mineral. Due to its low hardness, it is susceptible to scratches, so it must be protected from contact with harder minerals. Ultrasonic cleaners and sudden temperature changes should also be avoided. ## Storage It is recommended to store chudobaite specimens in separate, padded collector boxes to prevent mechanical damage and abrasions. They should be protected from dust and moisture. Due to its rarity and delicacy, this is not a mineral intended for frequent handling.

External references

https://www.mindat.org/min-1043.html