Veatchite-<i>A</i>

Chemical formula: Sr<sub>2</sub>[B<sub>5</sub>O<sub>8</sub>(OH)]<sub>2</sub>[B(OH)<sub>3</sub>]·H<sub>2</sub>O

A rare strontium borate, forming colorless or white, platy crystals with a pearly luster, found in marine evaporites.

## Characteristics Veatchite-A is a hydrated strontium borate, belonging to the veatchite group. This mineral forms characteristic, thin, platy crystals, often with a rhombic or pseudohexagonal outline. They are typically colorless or white, sometimes with a yellowish tint. The crystals exhibit a pearly luster on cleavage surfaces and a vitreous luster on other faces. It is a brittle mineral. ## Physical Properties Veatchite-A is characterized by relatively low hardness, measuring 2 on the Mohs scale. Its density ranges from 2.66 to 2.69 g/cm³. It is transparent to translucent. It possesses perfect cleavage in one direction, which accounts for its platy appearance and pearly luster on flat surfaces. ## History and Name The mineral was named in honor of John Allen Veatch (1808-1870), who first discovered boron in California. Veatchite was originally described in 1938. Later studies revealed the existence of two polymorphs: veatchite-A (monoclinic) and veatchite-p (trigonal, now known as veatchite). Veatchite-A was formally recognized as a distinct mineral species in 1959. The type locality for both minerals is the borate deposit in Lang, Los Angeles County, California, USA.

Properties

Mohs hardness
2
Luster
Pearly, Vitreous
Streak
White
Density
2.66-2.69
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Key diagnostic features of veatchite-A include its platy crystal habit, perfect cleavage in one direction, pearly luster on cleavage surfaces, and low hardness. Its occurrence in association with other borates is also characteristic. ## Distinguishing from Similar Minerals Veatchite-A is very similar to its polymorph, veatchite (formerly veatchite-p), and distinguishing them without advanced studies (e.g., X-ray diffraction) is practically impossible. It can be confused with other colorless, platy minerals with a pearly luster, such as gypsum or some micas, but it differs from them in its environment of occurrence and mineral association (other borates). ## Crystal Forms It forms thin to thick, platy crystals, often with a rhombic or hexagonal outline. Crystals can occur individually or form radial aggregates and rosettes.

Geological environment

## Genesis Veatchite-A is a sedimentary mineral, forming in marine evaporite basins. It crystallizes from solutions rich in boron and strontium under arid climatic conditions. It is a component of salt rocks, mainly anhydrite-gypsum. ## Mineral Associations It most commonly co-occurs with other borates, such as colemanite, howlite, ulexite, and gypsum. At the type locality (Lang, California), it was found in association with howlite and colemanite. ## Localities The most important and classic occurrences of this mineral are in the USA, in Los Angeles County, California (Sterling Borax mine in Lang). It has also been reported in England (Robin Hood's Bay, North Yorkshire), Kazakhstan (Inder boron deposit), and Germany (Rehden, Lower Saxony).

Rarity

Very rare

For collectors

## Quality Criteria Well-formed, sharp, transparent crystals with a distinct luster are most valued by collectors. Specimens with visible, individual crystals or aesthetic groups (rosettes) on a rock matrix are particularly sought after. Crystal size is also important, although even small but well-formed specimens are valuable due to the mineral's rarity. ## Popular Localities Classic and most well-known specimens come from the type locality in Lang, California, USA. Specimens from other localities, such as Kazakhstan or the United Kingdom, are also valued but less commonly found on the collector's market.

Care and storage

## Cleaning Specimens should be cleaned only very carefully, using a soft brush to remove dust. Due to its low hardness and perfect cleavage, the mineral is extremely susceptible to mechanical damage. Contact with water is not recommended, as it can damage the crystal surface or dissolve them. ## What to Avoid Avoid contact with water, acids, and other chemicals. The mineral is very soft, so it must be protected from scratching by harder minerals. It should not be heated or exposed to prolonged moisture. ## Storage It is recommended to store specimens in dry conditions, in closed display boxes, away from other minerals that could scratch them. Due to its brittleness, each specimen should be properly secured, preferably in a separate container.

Sources

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