Boggsite

Chemical formula: Na₃Ca₈(Si₇₇Al₁₉)O₁₉₂·₇₀H₂O

Boggsite is a rare mineral from the zeolite group, forming small, colorless or white crystals and spherulitic aggregates in amygdaloidal vesicles in basalts.

## Characteristics Boggsite is a hydrated calcium sodium aluminosilicate, belonging to the zeolite group. It occurs as very small, not exceeding 1 mm, tabular or prismatic crystals. Most often, it forms radial or spherulitic aggregates with a silky or pearly luster, filling voids in volcanic rocks. Individual crystals are usually colorless and transparent, while their aggregates are white. ## Physical Properties Boggsite crystals exhibit a hardness of approximately 4 on the Mohs scale. They have a vitreous luster, and a pearly or silky luster on the surfaces of aggregates. They are transparent to translucent. The mineral's density is approximately 2.16 g/cm³. ## Colors and Varieties This mineral is usually colorless or white. No color varieties or commercial varieties are distinguished. ## History and Name Boggsite was discovered and described in 1990 by Donald G. Howard, Robert C. Boggs, and William M. Wise. The mineral is named in honor of Robert C. Boggs (born 1940), an American mineral collector from Seattle, Washington, who first found this mineral and brought it to the attention of researchers. ## Applications Due to its rarity and small crystal size, boggsite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and micromounts.

Properties

Mohs hardness: 4
Luster: Vitreous, Pearly
Streak: White
Density: 2.16
Cleavage: Perfect on {100}, good on {010}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Orthorhombic

Diagnostic features

## Identification Amateur identification of boggsite is practically impossible due to its small size and resemblance to other zeolites. Identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical microanalysis (EDS/WDS). In a collection, it can be identified based on a label from a confirmed locality. ## Distinguishing from Similar Minerals Boggsite is visually indistinguishable from many other zeolites that form white, radial aggregates, such as thomsonite, scolecite, mesolite, or natrolite. It often co-occurs with them in the same vesicles. Definitive differentiation is only possible using laboratory methods. ## Crystal Forms It forms small, tabular crystals with a rectangular or square outline, often with truncated corners. These crystals combine into characteristic, fan-shaped or spherulitic (spherical) aggregates with a radial internal structure.

Geological environment

## Genesis Boggsite is a secondary mineral of hydrothermal origin. It crystallizes at low temperatures from aqueous solutions circulating in volcanic rocks, mainly basalts. It fills voids, such as gas vesicles (amygdales), forming druses and crusts on the walls of the cavities. ## Mineral Associations It most often co-occurs with other minerals from the zeolite group, such as thomsonite-Ca, clinoptilolite-Ca, mordenite, as well as with calcite and quartz (chalcedony). ## Localities The most important and classic localities for this mineral are: - Goble, Columbia County, Oregon, USA (type locality) - Highwood Mountains, Chouteau County, Montana, USA - Poona, Pune District, Maharashtra, India - Isle of Skye, Scotland, United Kingdom - Breiðdalur, Eastern Region, Iceland

Rarity

Very rare

For collectors

## Quality Criteria Boggsite's collector appeal depends primarily on the quality of the specimen as a whole, rather than the mineral itself, which is usually microscopic. The most prized specimens are those where white, well-formed boggsite spherulites create an aesthetic contrast with the dark host rock (basalt). Association with other colorful minerals, such as orange thomsonite, is also important. Since it is a micromount mineral, the perfection and undamaged state of the delicate aggregates are crucial. ## Popular Localities The most well-known specimens, often combining boggsite with thomsonite, come from localities in Oregon, USA, and from quarries near Poona, India. Specimens from these locations are most commonly found in specialized collections.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using a soft brush to remove dust. They can be rinsed in distilled water, avoiding a strong stream. Ultrasonic cleaners should be avoided, as they can damage delicate crystals. ## What to Avoid Avoid contact with acids and other aggressive chemicals. As a zeolite, boggsite is sensitive to high temperatures, which can cause it to lose water from its structure and suffer permanent damage. It should not be heated or exposed to prolonged strong sunlight. ## Storage Boggsite specimens, especially micromounts, are best stored in sealed, transparent boxes (e.g., "membrane box" or "micromount box") that protect them from dust, mechanical damage, and sudden changes in humidity.

Sources

IMA Mineral List (CNMNC)