Wonesite

Chemical formula: (Na,K,◻)(Mg,Fe²⁺,Al,Fe³⁺)₆(Si,Al)₈O₂₀(OH,F)₄

Wonesite is a rare mica group mineral, characterized by its golden-brown color and perfect cleavage, discovered in 1981 in Vermont, USA.

## Characteristics Wonesite is a trioctahedral mica group mineral, closely related to biotite and phlogopite. It forms small, tabular or platy crystals, often aggregated into scaly masses. Its characteristic features include a golden-yellow to brown color and perfect, unidirectional cleavage, allowing for easy separation of thin, flexible lamellae. ## Physical Properties This mineral is relatively soft, with a Mohs hardness of 2.5-3. Wonesite lamellae are transparent to translucent and exhibit a vitreous luster on cleavage surfaces. It is light, and its thin plates are flexible. ## Colors and Varieties The typical color of wonesite is golden-yellow to brown. No named color varieties or commercial varieties are distinguished. ## History and Name The mineral is named in honor of David R. Wones (1932-1984), an American petrologist and mineralogist from Virginia Polytechnic Institute and State University, for his contributions to mica research. Wonesite was described and approved as a new mineral in 1981, with its type locality being the Post Pond Volcanics formation in Vermont, USA. ## Uses Due to its rarity and small crystal size, wonesite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals, particularly those from the mica group.

Properties

Mohs hardness
2.5-3
Luster
Vitreous
Streak
White
Density
0
Cleavage
{001}
Fracture
Micaceous
Transparency
Transparent,Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Key diagnostic features of wonesite include its golden-brown color, micaceous appearance (lamellar aggregates), and perfect cleavage in one direction, allowing for the separation of thin, flexible plates. It is a relatively soft mineral. ## Distinguishing from Similar Minerals It can be confused with other micas of similar color, such as phlogopite or some varieties of biotite. Definitive differentiation from these more common minerals requires advanced analytical methods, such as chemical analysis or X-ray diffraction, as physical characteristics are very similar. ## Crystal Forms Wonesite forms small, tabular crystals with a pseudohexagonal outline. It most commonly occurs as scaly or platy aggregates and disseminations within the host rock.

Geological environment

## Genesis Wonesite forms under conditions of regional metamorphism, in rocks such as amphibolites and gneisses. It is a mineral associated with fault zones and metasomatic processes, where changes in the chemical composition of rocks occur under the influence of hot solutions. ## Mineral Associations At its type locality, wonesite coexists with minerals such as quartz, albite, microcline, actinolite, talc, titanite, apatite, pyrrhotite, and chalcopyrite. ## Localities The most important and well-documented occurrence of wonesite is its type locality in the Post Pond Volcanics, Windsor County, Vermont, USA. This is the only locality from which well-characterized specimens of this mineral originate.

Rarity

Very rare

For collectors

## Quality Criteria For collectors, the most desirable specimens are those with clearly visible, well-formed aggregates of wonesite lamellae, contrasting with a light host rock (e.g., quartz). The size of the aggregates and the intensity of the golden-brown color enhance the attractiveness of the specimen. Due to its rarity, any specimen with confirmed identity is valuable. ## Popular Localities The only source of collectible specimens is the type locality in Vermont, USA. Material from this location is extremely rare on the market.

Care and storage

## Cleaning Wonesite specimens should be cleaned very carefully, using a soft brush to remove dust. Compressed air can be used from a safe distance. Avoid contact with water, which can penetrate between the lamellae and weaken the aggregate structure. ## What to Avoid All chemicals, acids, and detergents should be avoided. The mineral is soft and susceptible to scratches and mechanical damage, such as the separation of lamellae. It should not be heated or exposed to prolonged moisture. ## Storage Wonesite specimens are best stored in closed display boxes to protect them from dust and mechanical damage. Due to its fragility, avoid placing other minerals on top of it.

External references

Sources

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