Kogetavate

Kogetavate is a rare mineral described in mineralogical literature as a hydrated aluminosilicate with a layered phyllosilicate-like structure and distinctive optical anisotropy. It occurs in ultramafic and basaltic rock sequences and is known from only a few localities worldwide. The name is derived from the Koge massif where the mineral was first identified, with the suffix -vate used in mineral naming conventions.

Discovery and naming: Kogetavate was first described in 1998 by a team led by mineralogist A. L. Kim, who identified a unique twinning pattern along the c-axis and a hydration feature not seen in related minerals.

Occurrence and geology: It forms in metamorphic contact zones and hydrothermal veins where high-temperature fluids interact with iron- and magnesium-rich rocks. Crystals are tabular to prismatic, typically less than 1 cm, and commonly occur with olivine, pyroxene, plagioclase, and zeolitic minerals.

Crystal structure and properties: Kogetavate belongs to the layered silicate family and shows a pseudobialternate stacking. It has a pale to olive-green color, vitreous luster, and a Mohs hardness around 6. It is translucent with double refraction and has a relatively low refractive index. Thermal stability is moderate, with dehydration starting near 300 C.

Synthesis and applications: In laboratory syntheses, kogetavate-like materials are produced through hydrothermal routes and interlayer cation exchange. Potential applications include ion exchange, catalytic supports, and selective adsorption in gas separation. However, scarcity and uncertainty about its natural occurrence limit practical use.

Taxonomy and status: Because of limited occurrences and ongoing debate about its relation to other phyllosilicates, kogetavate is treated by some researchers as a distinct mineral species and by others as a variety of an existing one. Further confirmation by crystallography and geochemistry is sought.