Slavíkite

Slavíkite (IMA symbol: Sví^[1]) is a mineral consisting of a hydrous basic magnesium ferric sulfate with the chemical formula (H₃O⁺)₃Mg₆Fe₁₅(SO₄)₂₁(OH)₁₈·98H₂O and is an oxidation product of pyrite in shales and slate from Bohemia.^[2] It was named in 1926 in honor of František Slavík, who was the Charles University in Prague where he was Dean of the Faculty of Science from 1924 to 1925 and Rector from 1937 to 1938.^[3]

Slavíkite
Alpersite crystals (white) with slavíkite
General
Category	Minerals
Formula	(H3O+)3Mg6Fe15(SO4)21(OH)18·98H2O
IMA symbol	Sví
Crystal system	Trigonal
Crystal class	Rhombohedral (3m) H-M symbol: (3m)
Identification
Color	Pale yellow, pale yellow-green
Mohs scale hardness	3.5
Luster	Vitreous, Dull
Specific gravity	1.905 - 1.99