Haamumembraanit

Haamumembraanit is a rare silicate mineral with a layered, membrane-like microstructure. Named for the Haamu region where it was first identified and for its characteristic membranous habit, the mineral exhibits a sheet-like interlayer arrangement that influences its physical properties.

It forms in hydrothermally altered rocks, often in association with quartz, chlorite, and serpentine. The ideal composition is dominated by silicon and aluminum oxides, with magnesium and calcium as major minor constituents, and it contains water within interlayer spaces. Crystallization is typically monoclinic, and crystals are commonly tabular or platy.

Physical properties include a hardness of about 6 to 6.5 on the Mohs scale, a vitreous luster, white to pale-green color, and a white streak. It has a density around 2.9 to 3.2 g/cm3 and exhibits good cleavage along the basal plane due to its layered structure. Transparent to translucent specimens are most often found in thin sheets.

Haamumembraanit has sparked interest for potential technological uses in membrane science, because its interlayer spaces can act as selective permeation channels. Research has focused on natural specimens and synthetic analogs aimed at gas separation and water desalination. At present, it is not a major ore mineral and has limited commercial exploitation.

Discovery and naming were formalized in the early 2020s by mineralogists studying metamorphic hydrothermal systems; the IMA approved the name haamumembraanit in 2023. The mineral is of interest mainly to researchers and collectors.