Kolicite

Chemical formula: Zn₂+₄Mn₂+₇(As₅+O₄)₂(SiO₄)₂(OH)₈

Kolicite is a very rare zinc manganese arsenate-silicate, forming small, orange-yellow crystals, known mainly from Franklin, USA.

## Characteristics Kolicite is a complex zinc and manganese arsenate and silicate, occurring extremely rarely. It forms small, tabular or nearly isometric crystals, rarely exceeding 1 mm in size. It is most often found in the form of small aggregates, coatings, and veins, composed of subparallel crystals. Its color is characteristic and ranges from intense orange-yellow to yellow-orange. ## Physical properties This mineral is relatively soft, with a Mohs hardness of 4.5. It exhibits a vitreous luster, transitioning to subadamantine on some surfaces. It is transparent to translucent. Its density is approximately 4.1 g/cm³. ## Colors and varieties Kolicite does not form color varieties, and its color is constant, falling within the range of orange-yellow hues. No commercial varieties of this mineral are known. ## History and name The mineral's name honors John M. Kolic (born 1945), an American chemist and mineral collector from New Jersey, who discovered the first specimens. Kolicite was described as a new mineral species in 1979 by Paul J. Dunn, Donald R. Peacor, and B. D. Sturman. The type locality is the Sterling Mine in Sterling Hill, Ogdensburg, Sussex County (New Jersey, USA). ## Applications Due to its extreme rarity and small crystal size, kolicite has no industrial applications. It is solely an object of scientific interest and a prized acquisition for specialized mineral collectors, especially micromounts.

Properties

Mohs hardness: 4.5
Luster: Vitreous to Sub-Adamantine
Streak: Light yellow
Density: 4.1
Cleavage: Perfect on {001}
Fracture: Uneven
Transparency: Transparent to Translucent
Crystal system: Triclinic

Diagnostic features

## Identification Key features for identifying kolicite are its characteristic orange-yellow color, perfect cleavage in one direction, and specific occurrence environment. It occurs as very small, tabular crystals forming aggregates. ## Distinguishing from similar minerals Kolicite can be confused with other orange minerals from Franklin and Sterling Hill, such as hodgkinsonite or clinohedrite. Hodgkinsonite typically forms larger, prismatic crystals with a different habit. Clinohedrite, although similar in color, is characterized by intense orange fluorescence under ultraviolet light, which kolicite does not exhibit. ## Crystal forms Kolicite crystals are tabular, often flattened parallel to the basal plane. They usually occur as radial or subparallel aggregates, forming coatings and fillings in rock fractures.

Geological environment

## Genesis Kolicite is a secondary hydrothermal mineral that formed within a metamorphosed, stratiform zinc and manganese ore deposit. Its genesis is closely related to the unique chemical conditions prevailing in the Franklin deposit in New Jersey. ## Mineral associations This mineral occurs in association with other, often rare, minerals from the Franklin deposit. The most common associations include willemite, franklinite, zincite, hodgkinsonite, clinohedrite, datolite, and baryte. ## Localities Kolicite is an extremely rare mineral, and its main and practically only occurrence of collector quality is the type locality – the Sterling Mine, Sterling Hill, Ogdensburg, New Jersey, USA. It has also been reported in trace amounts in the Franklin mine.

Rarity

Very rare

For collectors

## Quality criteria The most highly valued kolicite specimens are those characterized by rich crystallization on a relatively large surface of the rock matrix. The intensity and purity of the orange-yellow color are important, as well as the size and sharpness of the edges of individual crystals. Visually attractive associations with other rare minerals from Franklin, such as clinohedrite or hodgkinsonite, add additional value. ## Popular localities The only source of valuable collector specimens of kolicite is the Franklin-Sterling Hill mine complex in New Jersey, USA. Specimens from this locality are considered mineralogical classics and are highly sought after by collectors specializing in minerals from this deposit and in micromounts.

Care and storage

## Cleaning Kolicite specimens should be cleaned very carefully, using a soft brush and distilled water to remove dust and loose debris. Ultrasonic cleaners or strong water jets are not recommended, as they could damage the delicate crystals. ## What to avoid The mineral is relatively soft (hardness 4.5), so it should be protected from scratching by harder minerals. Contact with acids and other aggressive chemicals should be avoided. As an arsenate, basic precautions should be observed – it is recommended to wash hands after handling the specimen. ## Storage Collectible kolicite specimens, especially micromounts, are best stored in closed, padded boxes that protect them from dust, light, and mechanical damage. They should be kept separate from other, harder minerals.

Sources

IMA Mineral List (CNMNC)