Natural state of scandium production: scattered but not scarce

Scandium is a typical dispersed lithophile element, but it is not rare.  Its average abundance in the crust is 22-30 PPM (i.e. 22-30 g/t, converted to 35-48 g/t scandium trioxide), much higher than Ag, Au, Pb, Sb, Mo, Hg, W and Bi, and comparable to the abundance of B, Br, Sn, Ge and As.  

 In nature, scandium is not affected by REDOX, it is difficult to reduce to metal, and it rarely forms significant enrichment (deposits), but is widely dispersed in various rock-forming minerals (especially magnesium and iron silicates) and scandium minerals.  

There are more than 800 scandium minerals in nature, but few minerals with scandium trioxide content >0.05%.  At present, the only known independent scandium minerals are scandium yttrium ((Sc,Y)2Si2O7, Sc2O3 content 33.8%-42.3%), scandium hydrate (SCPO4.2H2O, Sc2O3 content 39.22%), beryllium-silicon scandium (Be3(Sc,  Al)2Si6O18,Sc2O3 content is 14.6%), zirconium scandium yttrium ((Sc,Zr)2Si2O7) and titanosilicate thin gold (Sc(Nb,Ti,Si)2O5, Sc2O3 content is 18.0%-20.0%).  It is rare in nature.