Class : Silicates
    Subclass : Sorosilicates
    Crystal system : Monoclinic
    Chemistry : (Sc,Y)₂Si₂O₇
    Rarity : Rare to very rare

Thortveitite is, with kolbeckite, practically the only scandium mineral. It is a very rare mineral found exclusively in granitic pegmatites, in association with classic silicates (feldspars, micas, quartz, beryl, etc...), rare earth minerals and ilmenorutile. Its composition is fluctuating, scandium can be replaced in significant quantities by yttrium, zirconium, aluminum, iron or rare earths. It was named in honor of the Norwegian mineralogist Olaus Thortveit who discovered it. Thortveitite crystals are elongated prisms, sometimes flattened. It is a brittle mineral, greenish gray to black in color. It is the main ore of scandium, a rare metal used in the metallurgical and aeronautical industries.

Main photo : Thortveitite from Undeland, Evje, Norway © Rob Lavinsky

Twinning on (110) is known.

No fakes listed for this mineral species.