Fabritzite

Chemical formula: Zn<sup>2+</sup><sub>9</sub>(S<sup>6+</sup>O<sub>4</sub>)<sub>2</sub>(OH)<sub>12</sub>Cl<sub>2</sub>·6H<sub>2</sub>O

Fabrycite is a very rare, secondary zinc sulfate, forming tiny, platy crystals of white or bluish-green color.

## Characteristics Fabrycite is a hydrated, basic zinc sulfate with added chlorine. It occurs as very small, hexagonal or pseudohexagonal crystals with a platy habit, rarely exceeding 0.2 mm in size. These crystals form rosetted or spherical aggregates, as well as thin coatings and crusts on rock surfaces. Due to the small size of the crystals, its macroscopic features are difficult to observe with the naked eye. ## Physical Properties Fabrycite crystals exhibit a pearly luster on basal surfaces and a vitreous luster on other faces. It is a soft mineral, with a Mohs hardness of 2. It is transparent to translucent. The calculated density is 3.42 g/cm³. ## Colors and Varieties Fabrycite is colorless, white, or has a delicate bluish-green tint. No varieties have been distinguished. ## History and Name The mineral was approved by the IMA in 2022 (IMA 2022-084). Its name honors Hubert Fabritz (1930-2019), a German mineralogist and curator of the mineralogical collection at the Natural History Museum in Mainz, in recognition of his contribution to the study of the mineralogy of metallurgical slags in the Eifel region. It was discovered at the slag heap of the former Binsfeldhammer zinc smelter in Stolberg, Germany. ## Uses Fabrycite has no practical application. It is of interest only to collectors specializing in rare minerals and microminerals.

Properties

Mohs hardness
2
Luster
Pearly, Vitreous
Streak
White
Density
3.42
Cleavage
Perfect on {0001}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Trigonal

Diagnostic features

## Identification Identification of fabrycite is possible only through advanced analytical methods, such as Raman spectroscopy or micro-area chemical analysis (EDS/WDS). In collector conditions, identification is based on knowledge of the locality, the characteristic morphology of small, platy crystals in rosetted aggregates, and coexisting minerals. ## Distinguishing from Similar Minerals Fabrycite can be confused with other secondary zinc sulfates, such as namuwite, gunningite, or lannonite, which can form visually similar coatings. Definitive differentiation requires specialized studies. ## Crystal Forms It forms thin, platy, hexagonal crystals that combine into rosetted or spherical aggregates. It also occurs as thin crusts and coatings.

Geological environment

## Genesis Fabrycite is a secondary mineral, formed as a result of weathering processes on the slag heaps of former zinc smelters. It forms in an environment rich in zinc, sulfates, and chlorine, under low-temperature conditions. It is an anthropogenic product, associated with industrial activity. ## Mineral Associations At the type locality (Binsfeldhammer, Germany), it coexists with other rare secondary minerals such as anglesite, simonkolleite, hydrocerussite, laurionite, as well as gypsum and calcite. ## Localities The only confirmed occurrence of fabrycite in the world is the slag heap of the Binsfeldhammer zinc smelter in Stolberg, North Rhine-Westphalia, Germany.

Rarity

Extremely rare

For collectors

## Quality Criteria As a micromineral, the collector value of fabrycite depends on the size and quality of the formation of rosetted crystal aggregates. Specimens with clearly formed, undamaged aggregates on a contrasting matrix are most desirable. A rich association with other rare secondary minerals is also important. ## Popular Localities The only source of specimens is the type locality - the Binsfeldhammer slag heap in Germany.

Care and storage

## Cleaning Fabrycite specimens should not be cleaned mechanically or chemically. Any attempts at cleaning, even with water, can damage the delicate crystals. The safest method is to remove dust using a soft brush or a photographic air blower. ## What to Avoid Avoid contact with water and any chemicals. The mineral is likely sensitive to changes in humidity and temperature. It should not be exposed to direct sunlight. ## Storage Fabrycite specimens, as microminerals, should be stored exclusively in sealed, closable "micromount" boxes to protect them from dust, mechanical damage, and changes in ambient humidity.

Sources

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