Rouxelite

Chemical formula: Cu₁+₂Hg₂+Pb₂+₂₂Sb₃+₂₈S₂-₆₄(O,S₂-)₂

Rouxelite is a very rare, lead-gray mineral from the sulfosalt group, found in hydrothermal deposits in France.

## Characteristics Rouxelite is a very rare, complex sulfosalt of lead, antimony, copper, and mercury. It occurs as small, tabular or bladed crystals, usually not exceeding 0.5 mm in length. It forms aggregates with other sulfosalts. Its color is lead-gray, and on a fresh surface, it exhibits a metallic luster. ## Physical Properties This mineral is opaque and has a metallic luster. Its Mohs hardness is approximately 3.5, and its density, calculated based on the chemical formula and unit cell parameters, is 6.28 g/cm³. ## History and Name It was discovered in the La Chapelle-en-Valgaudémar mine in the Provence-Alpes-Côte d'Azur region of France. Approved as a new mineral by the IMA in 2003 (IMA2003-048). The name honors Michel Rouxel, a French mineral collector who found the first specimens.

Properties

Mohs hardness: 3.5
Luster: Metallic
Streak: Black
Density: 6.28
Cleavage: Perfect on {001}
Fracture: Uneven
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of rouxelitem is possible almost exclusively using advanced laboratory methods, such as chemical analysis (EDS) and X-ray structural analysis (XRD). Visually, it is indistinguishable from many other similar sulfosalts. ## Distinguishing from similar minerals It can be confused with numerous other lead and antimony sulfosalts, such as zinkenite, plagionite, or semseyite. Definitive differentiation requires specialized analytical equipment to confirm the presence of copper and mercury in its composition. ## Crystal forms It forms very small, elongated, bladed or tabular crystals, often grouped into small aggregates.

Geological environment

## Genesis Rouxelite forms in low-temperature hydrothermal veins cutting metamorphic rocks (gneisses). It is a product of crystallization from solutions rich in lead, antimony, sulfur, copper, and mercury. ## Mineral associations It co-occurs with other sulfosalts, such as zinkenite, plagionite, semseyite, as well as with quartz, sphalerite, pyrite, and chalcopyrite. ## Localities The only confirmed locality for rouxelitem worldwide is its type locality - the La Chapelle-en-Valgaudémar mine (Jas Roux) in the Hautes-Alpes department, France.

Rarity

Extremely rare

For collectors

## Quality criteria As a "micromount" mineral, the value of rouxelitem is primarily determined by the quality and abundance of crystals on the rock matrix, as well as their good development. The most valuable specimens are those with clearly visible, sharp crystals, preferably accompanied by other rare sulfosalts. Laboratory confirmation of the mineral's identification is also crucial. ## Popular localities All known specimens come from a single location worldwide: the La Chapelle-en-Valgaudémar mine in France, which makes this locality extremely important for collectors specializing in rare minerals and sulfosalts.

Care and storage

## Cleaning Due to its extreme rarity and small crystal size, mechanical cleaning is not recommended. Any procedures should be performed exclusively by specialists under laboratory conditions. ## What to avoid Avoid contact with chemicals, acids, and bases. As a sulfosalt, it may be susceptible to oxidation in a humid environment. It should be protected from high temperatures and sudden temperature changes. ## Storage Rouxelite specimens should be stored under stable conditions, preferably in closed, padded "micromount" boxes, protecting them from dust, moisture, and mechanical damage.

Sources

IMA Mineral List (CNMNC)