Gwihabaite

Chemical formula: (N³⁻H₄)N⁵⁺O₃

Gwihabaite is a rare, naturally occurring ammonium nitrate, forming colorless or white, acicular crystals in arid climates.

## Characteristics Gwihabaite is a mineral form of ammonium nitrate. It occurs as delicate, acicular or fibrous crystals, which often form radial aggregates or crusty coatings on cave walls. The crystals are typically colorless to white and exhibit a vitreous luster. Due to its fragility and water solubility, it is a very unstable mineral in humid environments. ## Physical Properties Gwihabaite is very soft, with a Mohs hardness of approximately 2. It is a light mineral, with a density close to 1.72 g/cm³. The crystals are transparent to translucent. It exhibits perfect cleavage in one direction. ## History and Name The mineral was first described in 1996 by G. A. Martini. Its name comes from the Gcwihaba Cave (alternative spelling: Gwihaba) in Botswana, where it was discovered. This is its type locality. ## Uses Gwihabaite has no industrial applications. It is solely an object of scientific and collecting interest as a rare, naturally occurring nitrate.

Properties

Mohs hardness: 2
Color: Colourless
Luster: Vitreous
Streak: White
Density: 1.77
Cleavage: Perfect on {010}
Fracture: Conchoidal
Transparency: Transparent
Crystal system: Orthorhombic

Diagnostic features

## Identification Key diagnostic features include its occurrence in dry cave environments, the formation of delicate, acicular crystals, and very high water solubility. It reacts violently with a drop of water, which is a characteristic test. It is very soft and light. ## Distinguishing from Similar Minerals It can be confused with other soluble nitrates or sulfates found in caves, such as nitrocalcite, nitromagnesite, or gypsum. It differs from gypsum by its much greater water solubility. Accurate identification from other nitrates often requires chemical analysis. ## Crystal Forms Gwihabaite forms slender, elongated crystals with an acicular or fibrous habit. These crystals often arrange into radial or stellate aggregates, and also form delicate, fluffy coatings and crusts.

Geological environment

## Genesis Gwihabaite is a mineral of organic origin. It forms as a result of the reaction of ammonia, released during the decomposition of bat guano, with nitric acid. This process occurs in dry, well-ventilated caves where bat droppings accumulate over long periods. ## Mineral Associations It most commonly co-occurs with other minerals formed from bat guano, such as archerite, biphosphammite, as well as with gypsum and calcite, which form the cave's host rock. ## Localities The most important and type locality is Gcwihaba Cave in northwestern Botswana. It has also been identified in Murra-el-elevyn Cave in Western Australia. These are the only confirmed localities worldwide.

Rarity

Very rare

For collectors

## Quality Criteria The most prized gwihabaite specimens are those that exhibit well-formed, long needles forming rich, radial aggregates. Purity and absence of mechanical damage are important, which is difficult to achieve due to the mineral's fragility. Specimens on a rock matrix are more desirable than loose fragments. ## Popular Localities The vast majority, if not all, collector specimens come from the type locality – Gcwihaba Cave in Botswana. Material from other locations is practically unavailable on the market.

Care and storage

## Cleaning This mineral should not be cleaned with water. It is highly soluble in water. To remove dust, a very soft brush or carefully applied compressed air from a safe distance can be used. ## What to Avoid Contact with water and any moisture must be absolutely avoided, as it will cause the mineral to dissolve. The mineral is hygroscopic, meaning it absorbs moisture from the air – even high relative humidity can damage it. It should be protected from high temperatures and direct sunlight. ## Storage Gwihabaite specimens must be stored in sealed, dry containers, preferably with a desiccant (e.g., silica gel). They should be displayed away from heat and light sources, in stable temperature conditions.