Bottinoite

Chemical formula: Ni²⁺Sb⁵⁺₂(OH)₁₂·6H₂O

Bottinoite is a rare hydrated nickel hydroxyantimonate, forming characteristic pale blue crystals with a hexagonal outline.

## Characteristics Bottinoite is a rare secondary mineral from the bottinoite group, chemically classified as a hydrated nickel hydroxyantimonate. It occurs as small, hexagonal, tabular crystals, often grouped into rosette-like or radial aggregates. Its most characteristic feature is its delicate, pale blue or bluish-green color. ## Physical Properties This mineral is relatively soft, with a Mohs hardness of 3.5. The crystals exhibit a vitreous luster and are transparent. The density of bottinoite is approximately 2.83 g/cm³, which is an average value for minerals of this type. ## Colors and Varieties Bottinoite occurs in a uniform, pastel color range, from pale blue to light bluish-green. No color varieties or commercial varieties are distinguished. ## History and Name The mineral's name comes from its discovery locality – the Bottino mine in the municipality of Stazzema (Province of Lucca, Tuscany, Italy). It was first described in 1992 by T.M.M. Brizzi, G. Favreau, and P. Orlandi and approved by the International Mineralogical Association (IMA) in the same year. ## Uses Bottinoite has no industrial application. It is solely a mineral of scientific and collecting interest, sought after for its rarity and aesthetic appeal.

Properties

Mohs hardness
3.5
Luster
Vitreous
Streak
Very light blue
Density
2.83
Fracture
Conchoidal
Transparency
Transparent
Crystal system
Trigonal

Diagnostic features

## Identification Characteristic features of bottinoite include its pale blue color, hexagonal outline of tabular crystals, and occurrence in the oxidation zones of nickel and antimony ore deposits. A very light blue streak is also helpful in identification. ## Distinguishing from Similar Minerals Bottinoite is sometimes confused with other secondary nickel minerals of similar color, such as jamborite or reevesite, but it differs from them in crystal habit and chemical composition (presence of antimony). It is distinguished from chalcanthite by its insolubility in water and lower color intensity. ## Crystal Forms This mineral forms thin, tabular crystals with a hexagonal outline. These crystals often combine into small, rosette-like or radial aggregates, and also form thin coatings and crusts on the host rock.

Geological environment

## Genesis Bottinoite is a secondary mineral, forming in the oxidation (weathering) zones of hydrothermal ore deposits rich in nickel and antimony. It forms as a result of the reaction of surface waters with primary sulfides and arsenides. ## Mineral Associations This mineral often co-occurs with other minerals from the oxidation zone. In its type locality (Bottino mine), it was found in association with ullmannite, chalcostibite, bindheimite, brandholzite, and kermesite. ## Localities The most important and type locality for bottinoite is the Bottino mine in Tuscany, Italy. It is also known from several other global localities, including the Silbereck mine in Salzburg, Austria, and the Kmety mine in Nižná Slaná, Slovakia.

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens by collectors are those with well-formed, sharp crystals with a distinct hexagonal outline, forming aesthetic, rosette-like aggregates. The intensity and purity of the pale blue color also increase the specimen's value. Contrast with the host rock on which it occurs is also important. ## Popular Localities By far the most sought-after and classic specimens come from the type locality – the Bottino mine in Italy. Material from other known localities, such as Silbereck in Austria, is also valued, but Italian specimens are considered exemplary for this species.

Care and storage

## Cleaning Bottinoite specimens should be cleaned very carefully, using only a soft brush to remove dust. Due to its low hardness and potential reactivity, washing with water should be avoided, especially the use of ultrasonics. ## What to Avoid Contact with acids and other chemicals must be strictly avoided. The mineral is sensitive to high temperatures, which can lead to its dehydration and structural damage. It should also be protected from scratching by harder minerals. ## Storage Collector's specimens of bottinoite are best stored in separate, closed display boxes to avoid abrasion and contact with dust. It does not require special conditions regarding humidity or light, but it is recommended to keep it away from direct sunlight and heat sources.

External references

Sources

Read more