Raygrantite

Chemical formula: Pb²⁺₁₀Zn²⁺(S⁶⁺O₄)₆(SiO₄)₂(OH)₂

Raygrantite is a very rare, colorless lead and zinc sulfate and silicate, forming small, tabular crystals with a vitreous luster.

## Characteristics Raygrantite is a complex lead and zinc sulfate and silicate. It occurs as very small, colorless, tabular crystals, which can form rosette-like or radial aggregates. Individual crystals are transparent and exhibit a vitreous luster. Due to its chemical composition, this mineral is very heavy. ## Physical Properties Raygrantite is relatively soft, with a Mohs hardness of 3. Its density is high, at 6.374 g/cm³, which is typical for lead-rich minerals. The crystals are transparent and have a white streak. ## Colors and Varieties This mineral is colorless. No colored or commercial varieties have been identified. ## History and Name Raygrantite was named in honor of Ray Grant (b. 1957), an American mineral collector and author who specializes in microminerals and was the first to find specimens of this mineral. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2013. ## Applications Raygrantite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and micromounts.

Properties

Mohs hardness: 3
Luster: Vitreous
Streak: White
Density: 6.374
Cleavage: on {120}
Transparency: Transparent
Crystal system: Triclinic

Diagnostic features

## Identification Characteristic features of raygrantite include its colorless, tabular crystals, high density, relatively low hardness, and occurrence in paragenesis with other rare lead minerals. However, definitive identification requires advanced analytical methods, such as chemical analysis (EDS) or X-ray diffraction (XRD). ## Distinguishing from Similar Minerals It can be confused with other colorless, secondary lead minerals such as cerussite or anglesite. It is distinguished from them by its specific crystal habit (thin tablets), and above all, its unique chemical composition, being both a sulfate and a silicate. ## Crystal Forms Raygrantite forms thin, tabular crystals with a lath-like outline, often grouped into radial or rosette-like aggregates.

Geological environment

## Genesis It is a secondary mineral, formed in the oxidation zones (gossans) of polymetallic deposits rich in lead and zinc. It forms under arid, desert conditions, as a result of the alteration of primary sulfides. ## Mineral Associations At its type locality, it co-occurs with other rare secondary minerals such as cerussite, anglesite, wulfenite, mimetite, galena, sphalerite, quartz, as well as other lead sulfates and silicates, e.g., iranite, hemihedrite, and wickenburgite. ## Localities The only confirmed and described locality for raygrantite in the world is its type locality – the Evening Star Mine in Maricopa County, Arizona, USA.

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens are those with well-formed, sharp, transparent crystals forming aesthetic, radial aggregates on a contrasting rock matrix. Due to the microscopic size of the crystals, the quality of their formation and lack of damage, as well as the richness of paragenesis with other rare minerals, are crucial. ## Popular Localities The only source of raygrantite specimens is the Evening Star Mine in Arizona, USA. All specimens available on the collector's market originate from this single locality.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using a soft brush to remove dust. Due to its softness, ultrasonic cleaners and hard brushes should be avoided. Contact with water should be minimized. ## What to Avoid Avoid contact with acids and other chemicals that may damage the crystal surface. The mineral is sensitive to scratches and impacts. As a lead mineral, it is toxic – avoid inhaling dust and wash hands after each contact. ## Storage It is recommended to store specimens in stable, sealed containers (e.g., micromount boxes) to protect them from mechanical damage and dust. Keep it away from minerals that could scratch it.