Jerrygibbsite

Chemical formula: Mn²⁺₉(SiO₄)₄(OH)₂

Jerrygibbsite is a very rare, orange to brown manganese silicate, forming small, tabular crystals.

## Characteristics Jerrygibbsite is a mineral belonging to the silicate group, specifically to the nesosilicates. Its most characteristic feature is its intense, orange to reddish-brown color. It occurs as very small, tabular or bladed crystals, which rarely exceed 1-2 mm in length. These crystals often form radial or chaotic aggregates and clusters on the surface of the host rock, which is usually a hematite or manganese matrix. ## Physical Properties This mineral is characterized by a vitreous to slightly resinous luster. It is translucent to transparent in very thin fragments. Its Mohs hardness is about 4, making it relatively soft and susceptible to scratching. The density is significantly higher than average for non-metallic minerals, at approximately 4 g/cm³. ## Colors and Varieties Jerrygibbsite is prized for its vibrant coloration. Its color ranges from bright orange, through orange-red, to reddish-brown. No formal varieties of this mineral have been distinguished. ## History and Name The mineral was discovered in the Franklin Mine in Sussex County, New Jersey, USA. It was described and approved as a new mineral species in 1981. Its name honors Gerald V. Gibbs (born 1929), a distinguished American mineralogist and crystallographer from Virginia Polytechnic Institute and State University, for his contributions to silicate research. ## Uses Due to its extreme rarity and microscopic crystal sizes, jerrygibbsite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and minerals from the Franklin-Sterling Hill type locality.

Properties

Mohs hardness: 5.5
Color: Violet pink to pinkish violet
Luster: Vitreous
Streak: Pale pink
Density: 4.00
Cleavage: Parallel to {001}
Fracture: Irregular/Uneven
Transparency: Translucent
Crystal system: Orthorhombic

Diagnostic features

## Identification Jerrygibbsite can be identified by its characteristic, intense orange color, tabular crystal habit, and specific occurrence locality (Franklin, New Jersey). The luster is vitreous, and the crystals are typically very small. ## Distinguishing from Similar Minerals At first glance, it may be confused with other orange minerals from Franklin, such as leucophoenicite or hodgkinsonite. However, leucophoenicite has a different, more prismatic crystal habit and often a darker, reddish color. Hodgkinsonite forms crystals of a different shape and has perfect cleavage. Final differentiation often requires advanced analytical methods. ## Crystal Forms Jerrygibbsite crystallizes as thin, tabular or bladed crystals, often with a rectangular or hexagonal outline. These crystals form radial aggregates, rosettes, or irregular clusters on the surface of the host rock.

Geological environment

## Genesis Jerrygibbsite is a product of contact metamorphism of a zinc, iron, and manganese ore deposit. It forms under specific chemical conditions within metamorphosed carbonate rocks, rich in manganese. Its genesis is closely related to the unique geological environment of the Franklin deposit. ## Mineral Associations This mineral co-occurs with many other minerals from the Franklin deposit. It is most commonly associated with: willemite, zincite, franklinite, leucophoenicite, andradite, calcite, and barite. ## Localities The only confirmed locality for jerrygibbsite in the world is its type locality - the Franklin Mine in Sussex County, New Jersey, USA. It is an endemic mineral to this single deposit.

Rarity

Very rare

For collectors

## Quality Criteria The most desirable jerrygibbsite specimens for collectors are those with rich, dense clusters of well-formed, intensely orange crystals, contrasting with the dark host rock (matrix). The size of individual crystals, although always small, also affects value - the larger and better formed, the more valuable the specimen. The absence of damage to delicate crystals is also important. ## Popular Localities Since jerrygibbsite occurs in only one place in the world, all collector specimens come from the historic workings of the Franklin Mine in New Jersey, USA. This mine has been closed since 1954, meaning new specimens are no longer being acquired, and all available ones come from old collections.

Care and storage

## Cleaning Jerrygibbsite specimens should be cleaned with the utmost care, preferably using compressed air to remove dust. Due to the small size and fragility of the crystals, mechanical cleaning (e.g., with a brush) is highly risky. If liquid is necessary, a brief immersion in distilled water followed by thorough drying is recommended. ## What to Avoid Contact with acids and other aggressive chemicals, which can damage the mineral, must be absolutely avoided. Ultrasonic cleaners should not be used. The mineral is relatively soft, so it must be protected from scratching by harder minerals. ## Storage Jerrygibbsite specimens should be stored in separate, padded collector boxes to prevent abrasion and mechanical damage. Due to the microscopic nature of the crystals, a "micromount" box with appropriate protection is an ideal solution.