Samfowlerite

Chemical formula: Ca₁₄Mn₂+₃Zn₂+₂Be₂Be₆Si₁₄O₅₂(OH)₆

Samfowlerite is a very rare mineral from the silicate group, occurring as colorless to pale pink, tabular crystals.

## Characteristics Samfowlerite is a complex silicate of calcium, manganese, zinc, and beryllium. It forms very small, tabular or bladed crystals, typically not exceeding 1 mm in length. They are most often colorless, but can take on shades of pale pink or light brown. This mineral is transparent and characterized by a vitreous luster. ## Physical Properties Samfowlerite has a hardness of approximately 5 on the Mohs scale. Its crystals exhibit perfect cleavage in one direction, which is visible on the crystal surfaces. The mineral's density is about 3.11 g/cm³. ## Colors and Varieties This mineral is usually colorless, transitioning to pale pink or light brown. No distinct varieties have been identified. ## History and Name Samfowlerite was discovered in the Franklin Mine in Sussex County, New Jersey, USA. It was described and approved as a new mineral species in 1994. Its name honors Sam Fowler, a historian of the Franklin Mine and a collector of minerals from that region, who contributed to the preservation of the heritage of this famous locality. ## Uses Due to its extreme rarity and microscopic crystal sizes, samfowlerite has no industrial application. It is of purely scientific significance and is sought after by specialized collectors of systematic minerals and micromounts.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: White
Density: 3.11
Cleavage: Perfect on {001}
Fracture: Uneven
Transparency: Transparent
Crystal system: Triclinic

Diagnostic features

## Identification Amateur identification of samfowlerite is practically impossible. It requires specialized analytical methods, such as X-ray diffraction (XRD) and chemical microanalysis (EDS/WDS). In a collection, it can be recognized based on the label and comparison with photographic documentation from the type locality. Its tabular habit and co-occurrence with other rare minerals from Franklin are characteristic. ## Distinguishing from Similar Minerals It can be confused with other colorless, tabular silicate minerals, such as willemite or other rare minerals from Franklin. Definitive distinction is only possible using advanced laboratory techniques. ## Crystal Forms Samfowlerite forms thin, tabular crystals with a hexagonal or rectangular outline, often with truncated corners. They occur as single, isolated crystals or small groups growing on other minerals, mainly on willemite.

Geological environment

## Genesis Samfowlerite forms as a result of metamorphic processes acting on zinc, manganese, and iron ore deposits. Its formation is associated with hydrothermal recrystallization under specific chemical conditions, in the presence of beryllium, within metamorphosed carbonate rocks (marbles). ## Mineral Associations This mineral occurs in association with other, often rare minerals characteristic of the Franklin deposit. It is most commonly found in association with willemite, franklinite, andradite, esperite, clinohedrite, hardystonite, and zincite. ## Localities The only confirmed occurrence of samfowlerite in the world is its type locality - the Franklin Mine in Sussex County, New Jersey, USA. It is an endemic mineral to this deposit.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a samfowlerite specimen is assessed primarily based on the size and development of the crystals, even though they are always microscopic. The most valued specimens are those with well-formed, sharp, and transparent crystals that are clearly visible against the matrix. Color contrast with the substrate (e.g., with fluorescent willemite) also enhances aesthetic value. The presence of rare associated minerals is an additional advantage. ## Popular Localities All known samfowlerite specimens come from a single location worldwide: the Franklin Mine in New Jersey, USA. This is the classic and only locality for this mineral.

Care and storage

## Cleaning Specimens containing samfowlerite should be handled with utmost care. Due to the microscopic size of the crystals, mechanical cleaning is not recommended. If dust removal is necessary, compressed air can be used from a safe distance. Do not use water or any chemicals. ## What to Avoid Avoid contact with acids and other chemicals that can damage both samfowlerite and its associated minerals. Avoid vibrations, ultrasonics, and sudden temperature changes. The crystals are brittle and susceptible to mechanical damage. ## Storage Samfowlerite specimens, most often in the form of micromounts, should be stored in special, sealed boxes that protect them from dust and mechanical damage. Avoid exposure to direct sunlight, although it is not considered particularly harmful to this mineral.

Sources

IMA Mineral List (CNMNC)