Alarsite

[2] It occurs as brittle subhedral grains which exhibit trigonal symmetry.

It is semitransparent, colorless with pale yellow tints and shows a vitreous luster.

It is optically uniaxial (+) with refractive indices of nω = 1.596 and nε = 1.608.

It was reported from fumaroles in the Tolbachik volcano, Kamchatka, Far Eastern Region, Russia.

[3][4] It occurs in association with fedotovite, klyuchevskite, lammerite, nabokoite, atlasovite, langbeinite, hematite and tenorite.