Sklodowskite is a uranium mineral with the chemical formula: Mg(UO₂)₂(HSiO₄)₂·5H₂O. It is a secondary mineral which contains magnesium and is a bright yellow colour, its crystal habit is acicular, but can form in other shapes. It has a Mohs hardness of about 2-3. It is named after the maiden name of Marie Curie, Sklodowska. It is the magnesium analogue of the much more common uranium mineral Cuprosklodowskite, which contains copper instead.