Botryogen

Botryogen is a hydrous magnesium sulfate mineral with formula: MgFe(SO₄)₂(OH)·7H₂O. It is also known as quetenite.

It crystallizes in the monoclinic prismatic system and typically occurs as vitreous bright yellow to red botryoidal to reniform masses and radiating crystal prisms. Its specific gravity is 2 to 2.1 and its Mohs hardness is 2.