Lahustites

Lahustites are a fictional group of minerals described in speculative geology and used in teaching exercises to illustrate mineral description procedures. They are not recognized by current mineral databases.

The name is derived from the fictional Lahust region, where the mineral was originally described in hypothetical literature.

Lahustites are described as hydrated aluminum silicates with a layered structure consisting of aluminosilicate sheets joined by interlayer cations and water molecules. The composition is variable, with modest substitution of iron or magnesium for aluminum and a range of interlayer cations such as sodium, calcium, or potassium.

In the fictional accounts, lahustites crystallize in monoclinic or orthorhombic systems and show basal cleavage. Hardness is typically reported around 4 on the Mohs scale, with a specific gravity near 2.8–3.2. They are described as colorless to white in powder form, with pale earthy or glassy luster.

They are described to form by low-temperature alteration of feldspathic or ultramafic rocks in hydrothermal environments or during metamorphism, and can be synthesized under controlled laboratory conditions to study adsorption phenomena and water transport in layered silicates.

Although lahustites are widely referenced in fictional contexts, they have no verified occurrences in peer-reviewed mineralogical literature; they serve to illustrate the criteria used to delineate minerals and the process of classifying new species.