Rare-Element Granitic Pegmatites | Rare Earth and Critical ...
Rare-element granitic pegmatites represent highly concentrated sources of rare metals, including Li, Rb, Cs, Be, Sn, Nb, Ta, Zr, Y, REE, and U. In today's markets, pegmatites are the principal sources of Ta, and one pegmatite (Tanco, Canada) is the sole commercial producer of Cs for use as deep drilling fluid in the form of Cs formate solution.