Cattierite
Chemical formula: Co²⁺(S₂)²⁻
Cattierite is a rare cobalt sulfide from the pyrite group, forming metallic, cubic crystals, valued by systematic mineral collectors.
Properties
- Mohs hardness
- 4
- Luster
- Metallic
- Density
- 4.82
- Cleavage
- on {001}
- Transparency
- Opaque
- Crystal system
- Isometric
Diagnostic features
## Identification Characteristic features of cattierite include its regular, cubic crystal form, metallic luster, grayish-white color with a pinkish hue, and relatively high density. Its occurrence in association with other cobalt and nickel sulfides in sedimentary rocks is also an important clue. ## Distinguishing from Similar Minerals Cattierite can be confused with pyrite (FeS₂), which is usually yellow and harder (6-6.5). It can be distinguished from the similar-looking vaesite (NiS₂) based on chemical analysis (presence of cobalt instead of nickel). Galena (PbS) is much softer (2.5) and has a higher density (approx. 7.6 g/cm³). ## Crystal Forms It most commonly forms well-developed crystals with a cubic (hexoctahedral) habit, less often octahedral or in combinations of these forms. It also occurs in granular aggregates within other minerals.
Geological environment
## Genesis Cattierite is a low-temperature hydrothermal mineral. It forms under reducing conditions within sedimentary rocks, such as black shales or dolomites, often in the presence of organic matter. ## Mineral Associations This mineral co-occurs with other sulfides, mainly from the pyrite group, such as pyrite, vaesite, and marcasite. In its type locality, it was found in association with linnaeite, bornite, and chalcopyrite. ## Localities The most important and type locality is the Shinkolobwe mine in Haut-Katanga Province, Democratic Republic of Congo. It is also known from several other localities worldwide, including Jiangxi Province in China, Hesse in Germany, and Missouri in the USA, but it remains a rare mineral everywhere. ## Collector's Criteria The most prized specimens by collectors are those with sharp, well-formed cubic crystals exhibiting a mirror-like, metallic luster. A distinct pinkish hue and contrasting placement of crystals on the rock matrix enhance its attractiveness. Crystal size is a key factor – specimens with crystals exceeding a few millimeters are already considered exceptional. ## Popular Localities Undoubtedly, the most desirable and classic cattierite specimens come from its type locality – the Shinkolobwe mine in the Democratic Republic of Congo. Specimens from this location set the standard against which other finds are compared.
Rarity
Rare
For collectors
## Kryteria jakości Najbardziej cenione przez kolekcjonerów są okazy z ostrymi, dobrze wykształconymi sześciennymi kryształami o lustrzanym, metalicznym połysku. Atrakcyjność podnosi wyraźny różowawy odcień oraz kontrastowe umiejscowienie kryształów na matrycy skalnej. Wielkość kryształów jest kluczowym czynnikiem - okazy z kryształami przekraczającymi kilka milimetrów są już uważane za wyjątkowe. ## Popularne stanowiska Zdecydowanie najbardziej pożądane i klasyczne okazy cattierite pochodzą z jego lokalizacji typowej - kopalni Shinkolobwe w Demokratycznej Republice Konga. Okazy z tego miejsca stanowią standard, do którego porównywane są inne znaleziska.
Care and storage
## Cleaning Cattierite specimens should be cleaned very carefully, using a soft brush to remove dust. Due to its sulfide nature, contact with water should be kept to a minimum, and after any wet cleaning, the specimen should be thoroughly dried immediately. ## What to Avoid Avoid contact with chemicals, especially acids, which can react with sulfides. Prolonged exposure to humid air can lead to slow oxidation and tarnishing of crystal surfaces. It should be protected from impacts and scratching by harder minerals. ## Storage It is recommended to store cattierite in a dry place, preferably in a closed display case or box with a desiccant, to minimize the risk of oxidation. Exposure should be away from direct sunlight and heat sources.