Kalsilite (
K Al Si O4) is a vitreous white to grey
feldspathoid
The feldspathoids are a group of tectosilicate minerals which resemble feldspar
Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, pota ...
al
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
that is found in some potassium-rich
lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...
s, such as from
Chamengo Crater in
Uganda
Uganda, officially the Republic of Uganda, is a landlocked country in East Africa. It is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the ...
. It has a relative
hardness
In materials science, hardness (antonym: softness) is a measure of the resistance to plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by Pressing (metalworking), pressing or abrasion ...
of 5.5.
References
Webmineral.comHandbook of Mineralogy
Potassium minerals
Aluminium minerals
Feldspathoid
Hexagonal minerals
Minerals in space group 182
Minerals described in 1942
{{mineral-stub