Lawsonbauerite

Chemical formula: Mn<sup>2+</sup><sub>9</sub>Zn<sup>2+</sup><sub>4</sub>(S<sup>6+</sup>O<sub>4</sub>)<sub>2</sub>(OH)<sub>22</sub>·8H<sub>2</sub>O

A rare, hydrated manganese and zinc sulfate with a characteristic, bright orange color and fibrous aggregates.

## Characteristics Lawsonbauerite is a very rare, complex, hydrated hydroxyl sulfate of manganese and zinc. It forms characteristic, bright, orange-yellow to orange-red coatings and crusts. It typically occurs as microscopic, bladed or acicular crystals that form radial, fibrous, or spherulitic (spherical) aggregates. Individual crystals are too small to be seen with the naked eye, and the material has a felted or earthy appearance. ## Physical Properties Lawsonbauerite crystals are flexible and pliable. This mineral has a very low hardness, approximately 2 on the Mohs scale, which means it can be scratched with a fingernail. It has a silky luster, and in the case of earthy aggregates, a dull luster. It is translucent. ## Colors and Varieties Lawsonbauerite occurs in uniform, bright colors ranging from orange-yellow to orange-red. No color or commercial varieties are distinguished. ## History and Name The mineral was first described in 1979 by Pete J. Dunn, Donald R. Peacor, and B. Darko Sturman. Its name honors Lawson H. Bauer (1889-1954), a prominent chemist who worked for many years at the Franklin Mine in New Jersey and made significant contributions to the understanding of the mineralogy of this deposit. The type locality (locus typicus) is the Sterling Hill Mine in Ogdensburg, New Jersey, USA. ## Applications Lawsonbauerite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals or minerals from the Franklin-Sterling Hill deposit.

Properties

Mohs hardness
2
Luster
Silky
Streak
Light yellow
Density
2.98
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Lawsonbauerite can be identified by its unique, bright orange color, fibrous or felted habit, and very low hardness. Its origin, almost exclusively from the Franklin-Sterling Hill deposit, is also characteristic. ## Distinguishing from Similar Minerals It can be confused with other secondary, orange zinc and manganese minerals. It is distinguished from the similar-looking mooreite primarily by its color (mooreite is colorless to white) and crystallographic data. Final identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Crystal Forms It forms microscopic, elongated, bladed crystals that combine into radial, spherulitic, or fibrous aggregates. Rosette-like clusters or simply massive, earthy coatings on the host rock are less common.

Geological environment

## Genesis Lawsonbauerite is a secondary hydrothermal mineral, forming in the oxidation zone of zinc and manganese ore deposits. It forms as a result of the alteration of primary ore minerals under low-temperature conditions. It occurs in fractures and voids within zinc-manganese ores. ## Mineral Associations This mineral co-occurs with other rare secondary minerals from the Franklin-Sterling Hill deposit. It is most often associated with: zincite, franklinite, willemite, calcite, torreyite, mooreite, fluoborite, and sussexite. ## Localities Lawsonbauerite is an extremely rare mineral, known practically from only one location in the world. Confirmed localities are the Franklin Mine and the Sterling Hill Mine in Ogdensburg, Sussex County, New Jersey, USA. This deposit is its type locality and the main source of specimens.

Rarity

Very rare

For collectors

## Quality Criteria Most valued by collectors are specimens where lawsonbauerite forms rich, well-formed, spherical or radial aggregates with an intense orange color. Contrast with light host rock, most often white calcite, is also highly appreciated. Due to the microscopic size of the crystals, the value of a specimen is primarily determined by the abundance and aesthetics of the entire aggregate, rather than a single crystal. ## Popular Localities The only source of valuable collector specimens is the Franklin and Sterling Hill mine complex in New Jersey, USA. Specimens from this locality are classic and serve as a benchmark for this mineral.

Care and storage

## Cleaning Lawsonbauerite specimens are extremely delicate and sensitive. Wet cleaning should be avoided. Only very careful dust removal using a soft brush or a photographic air blower is permissible. Any contact with water or other liquids can damage or destroy the fragile aggregates. ## What to Avoid Water, chemicals (including acids and bases), ultrasound, and high temperatures must be strictly avoided. The mineral is very soft, so it should be protected from any mechanical contact and scratching. As a hydrated mineral, it may be sensitive to changes in humidity and desiccation. ## Storage It is recommended to store specimens in closed, padded collector boxes (micromount type) to protect them from dust, mechanical damage, and sudden changes in humidity. It should not be exposed to direct sunlight, which can cause fading over time.

Sources

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