Jouravskite

Properties

Mohs hardness

2.5

Luster

Vitreous

Streak

Pale yellow

Density

2.13

Cleavage

Good on {1010}

Fracture

Uneven

Transparency

Transparent to translucent

Crystal system

Hexagonal

Diagnostic features

## Identification Jouravskite is relatively easy to identify due to its characteristic, intense lemon-yellow color, acicular crystals, and association with manganese minerals. Its low hardness (approx. 2.5) and reaction with acids (CO₂ effervescence) are also diagnostic features, although these tests are destructive and not recommended for collector specimens. ## Distinguishing from Similar Minerals It can be confused with other minerals from the ettringite group, such as thaumasite or sturmanite. It is distinguished from thaumasite by its intensely yellow color (thaumasite is usually colorless or white). Sturmanite can also be yellow, but often has a darker, more orange or brownish hue, and definitive differentiation requires advanced chemical analysis. ## Crystal Forms Jouravskite crystallizes in hexagonal, prismatic, or acicular forms, often elongated along the crystallographic axis. These crystals typically form radial, stellate, or fibrous aggregates, as well as compact crusts on host rocks.

Geological environment

## Genesis Jouravskite is a secondary mineral, formed in the oxidation zones of manganese deposits. It forms as a result of low-temperature hydrothermal processes or weathering, in an environment rich in calcium, sulfates, and carbonates. It most commonly occurs in vugs and fissures of metamorphic rocks containing manganese ores. ## Mineral Associations This mineral often co-occurs with other manganese minerals, such as braunite, hausmannite, bixbyite, as well as calcite, barite, marokite, and hematite. Other minerals from the ettringite group, such as thaumasite, can also be found in its paragenesis. ## Localities The most important and well-known jouravskite localities in the world are in South Africa, in the Kalahari manganese field, particularly in the N’Chwaning I, II, and III and Wessels mines. The best collector specimens originate from there. This mineral has also been found at the type locality in Morocco (Tachgagalt mine) and in several other locations worldwide, including Russia (Urals).

Rarity

Rare

For collectors

## Quality Criteria The most highly valued jouravskite specimens are characterized by an intense, pure, lemon-yellow color. The crystal form is crucial – well-formed, sharply terminated needles forming aesthetic, radial aggregates are sought after. Contrast with a dark host rock (e.g., with hausmannite) significantly enhances the visual appeal and value of the specimen. The size of the aggregates and the absence of damage are also important factors. ## Popular Localities By far the most desired specimens by collectors come from the Kalahari basin mines in South Africa (e.g., N'Chwaning). Specimens from these localities are considered the global standard of quality for this mineral.

Care and storage

## Cleaning Jouravskite specimens are extremely delicate and sensitive to water. Mechanical cleaning is highly risky. If necessary, compressed air (from a safe distance) can be used to remove loose dust. Contact with water, which can damage or dissolve the crystals, should be avoided. ## What to Avoid Contact with water, acids, and other chemicals must be absolutely avoided. The mineral is very soft and brittle, susceptible to mechanical damage. It should be protected from high temperatures and direct sunlight, which can cause dehydration and loss of color. ## Storage It is recommended to store specimens in closed, stable containers (e.g., "micromount boxes") to protect them from dust, moisture, and physical damage. They should ideally be kept in a dry place at a constant temperature.

Sources

• IMA Mineral List (CNMNC)