Galeite
Chemical formula: Na<sub>15</sub>(S<sup>6+</sup>O<sub>4</sub>)<sub>5</sub>ClF<sub>4</sub>
Galeite is a rare sodium, chlorine, and fluorine sulfate, found in evaporite deposits and soluble in water.
Description
## Characteristics Galeite is a sulfate mineral, chemically classified as a sodium sulfate with added chlorine and fluorine. It forms small, most often colorless or white crystals with a vitreous luster. It usually occurs as small, tabular or pyramidal crystals, often intergrown with other salt minerals, such as halite or thenardite. Due to its solubility, well-formed, freestanding crystals are rare. ## Physical Properties This mineral is relatively soft, with a Mohs hardness of 2.5, meaning it can be scratched with a fingernail. It has a density of 2.61 g/cm³, making it slightly heavier than halite. It exhibits perfect cleavage in one direction, causing it to easily split into thin lamellae. Its fracture is conchoidal. It is transparent to translucent. ## Colors and Varieties Galeite is most often colorless, white, or grayish. No colored varieties or trade names are distinguished. ## History and Name The mineral was described in 1955 by Deane K. Smith Jr., Adolph Pabst, and Joseph J. Glass. The name "galeite" was given in honor of William Alexander Gale (1897–1983), a chemist at the American Potash and Chemical Corporation, who conducted extensive research on salt deposits in Searles Lake, California, where the mineral was first identified. ## Uses Galeite has no industrial application. It is solely an object of scientific interest and is valued by collectors specializing in rare minerals or minerals from specific locations.
Diagnostic features
## Identification Key diagnostic features of galeite are its low hardness (2.5), perfect cleavage in one direction, vitreous luster, and occurrence environment (salt evaporites). A destructive but definitive test is its easy solubility in water. It occurs in characteristic association with other salt minerals. ## Distinguishing from Similar Minerals Galeite can be confused with other colorless evaporite minerals. It is distinguished from halite by the lack of a salty taste and its trigonal crystal form (halite is isometric). It differs from thenardite by its crystal habit and perfect cleavage (thenardite has good cleavage). It is significantly harder than gypsum (gypsum's hardness is 2). ## Crystal Forms Galeite crystallizes in the trigonal system. It most often forms small, sharply pointed pyramidal crystals or flat, tabular crystals with a hexagonal outline. It also occurs as granular aggregates intergrown with other minerals.
Geological environment
## Genesis Galeite is a mineral of evaporitic origin. It forms by precipitation from highly saline, sodium-, sulfate-, chloride-, and fluoride-rich waters in drying alkaline lakes under desert or semi-desert climatic conditions. ## Mineral Associations This mineral typically co-occurs with other evaporites. Its most common associated minerals are schairerite, halite, thenardite, sulfohalite, and tychite. Co-occurrence with these minerals is a strong diagnostic indicator. ## Localities The most important and classic locality for galeite is Searles Lake in San Bernardino County, California (USA), from which the best specimens originate. It has also been reported in similar geological formations in Uganda (Lake Katwe) and China.
Rarity
Very rare
Collector aspects
## Quality Criteria The collector's value of galeite primarily depends on its rarity and origin. Specimens with well-formed, sharp, and transparent crystals are most prized, which is rare. Association with other rare minerals from Searles Lake, such as schairerite, is also of great importance. Specimens are usually small, often in the form of micromounts. ## Popular Localities The only source of specimens of collector's significance is its type locality – Searles Lake in California, USA. Specimens from other localities are extremely rare in collections.
Care and storage
## Cleaning Galeite is soluble in water, so under no circumstances should it be wet cleaned. To remove dust, use only a soft, dry brush or compressed air with low pressure. ## What to Avoid Contact with water, acids, and other liquids must be strictly avoided. The mineral is hygroscopic, meaning it can absorb moisture from the air, leading to its slow disintegration. It should be protected from high humidity and sudden temperature changes. ## Storage Galeite specimens are best stored in sealed, airtight containers (e.g., "perky boxes") with a desiccant (e.g., silica gel). Display should be in a dry room, away from sources of moisture.