Sulvanite

Chemical formula: Cu₂+₃V₃+S₂-₄

Sulvanite is a rare copper vanadium sulfide, forming metallic-lustered, brown crystals in the isometric system.

## Characteristics Sulvanite is a rare mineral from the sulfide group, chemically classified as a copper vanadium sulfide. Its name is derived from its chemical composition – sulfur and vanadium. It most often forms cubic or octahedral crystals, which rarely exceed a few millimeters in size. It also occurs as granular aggregates and masses filling small fractures in the host rock. A characteristic feature of sulvanite is its metallic luster and brown color with a pinkish or purplish hue. ## Physical Properties This mineral is relatively soft, with a Mohs hardness of 3.5. It is brittle and exhibits an uneven fracture. Its density is significant, approximately 4.6 g/cm³. It does not exhibit cleavage. The luster is strongly metallic, and the mineral is completely opaque. ## Colors and Varieties Sulvanite typically has a tin-bronze or brownish-pink color. On weathered surfaces, it may be covered with a darker, dull tarnish. No named varieties of this mineral are distinguished. ## History and Name Sulvanite was first described in 1900 by George A. Goy, who identified it in material from the Edelweiss Mine in Salt Lake County, Utah, USA. The name, as mentioned, refers directly to its chemical composition – sulfur and vanadium. ## Uses Due to its rarity, sulvanite has no industrial significance. It is solely an object of interest for collectors of rare minerals and scientists.

Properties

Mohs hardness: 3.5
Luster: Metallic
Streak: Black
Density: 4.6
Cleavage: None
Fracture: Uneven
Transparency: Opaque
Crystal system: Cubic

Diagnostic features

## Identification Sulvanite can be identified by its characteristic brownish-pink color, strong metallic luster, and isometric, most often cubic, crystal form. Its black streak is also an important diagnostic feature. Its occurrence in association with other copper and vanadium minerals in a specific geological environment is a strong indication. ## Distinguishing from similar minerals Sulvanite is sometimes confused with bornite, especially when the latter has a fresh, brownish-pink surface. However, bornite quickly iridesces purple and blue, which sulvanite does not. Germanite has a similar appearance but is much rarer and usually has a more grayish hue. Certain distinction often requires chemical analysis. ## Crystal Forms Sulvanite crystals are usually small and well-formed, taking the shape of cubes, octahedra, and their combinations. They often occur as single crystals embedded in rock or in small vugs. It is also found as granular aggregates and masses filling veins.

Geological environment

## Genesis Sulvanite is a hydrothermal mineral. It forms in ore veins, usually in sedimentary rocks such as sandstones or dolomites. Its crystallization occurs under low to medium temperature conditions from solutions rich in copper, vanadium, and sulfur. ## Mineral associations This mineral often co-occurs with other copper sulfides and sulfosalts. The most common associated minerals include chalcopyrite, pyrite, digenite, covellite, as well as vanadium minerals like carnotite or tyuyamunite. In some localities, it is found together with enargite and luzonite. ## Localities The most important and classic sulvanite localities worldwide are the Edelweiss Mine in Utah (USA), where it was discovered, and the Burra deposit in South Australia, from which some of the best specimens originate. It also occurs in Kyrgyzstan (Kurama deposit), Argentina (Mendoza province), and Italy (Sardinia).

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens by collectors are those with sharp, well-formed crystals exhibiting a mirror-like, metallic luster and an intense, brownish-pink color. The absence of mechanical damage and attractive placement of crystals on a contrasting rock matrix are important. Specimens with crystals larger than a few millimeters are considered exceptional. ## Popular Localities By far the most sought-after sulvanite on the collector's market comes from the Burra mine in Australia. Specimens from there are characterized by exceptionally well-formed crystals, often forming spectacular vugs.

Care and storage

## Cleaning Sulvanite specimens should be cleaned very carefully, using a soft brush to remove dust. Compressed air can be used. Due to its brittleness and potential reactivity, washing in water, and especially using any detergents, should be avoided. ## What to avoid Contact with chemicals, especially acids, which can damage it, should be avoided. The mineral is sensitive to moisture and atmospheric changes, which can cause oxidation and dulling of the surface. It should not be heated or exposed to prolonged sunlight. ## Storage It is recommended to store sulvanite specimens in dry conditions, preferably in closed, padded collector boxes or display cases, to protect them from mechanical damage and atmospheric factors. Display should be in stable conditions, away from sources of moisture.

Sources

IMA Mineral List (CNMNC)