Formula: K₂Cu₃(SO₄)₃O

Species: Sulfates

Colour: Emerald green to grass green

Lustre: Vitreous, Silky

Hardness: 2½

Specific Gravity: 3.205

Crystal System: Monoclinic

Name: Named in honor of Sergei Aleksandrovich Fedotov (Сергей Александрович Федотов) (1931USSR–2019), volcanologist and seismologist, Director of the Institute of Volcanology, Petropavlovsk-Kamchatkskii, Russia.

Type Locality: Great Fissure eruption (Main Fracture) Tolbachik Volcanic field. Milkovsky District, Kamchatka Krai, Russia

Structurally related to euchlorine and puninite.