Thorite
Chemical compound
>
Thorite, SiO₄, is a rare nesosilicate of thorium that crystallizes in the tetragonal system and is isomorphous with zircon and hafnon. It is the most common mineral of thorium and is nearly always strongly radioactive. Wikipedia
Crystal system: Tetragonal
Cleavage: Distinct on
Color: Yellow-orange, brownish yellow, brownish black, black, green
Crystal class: Ditetragonal dipyramidal (4/mmm); H-M symbol: (4/m 2/m 2/m)
Crystal habit: In square prisms, or pseudo-octahedral crystals; also massive
Fracture: Conchoidal