The Greenbushes ore body is a highly mineralized zoned pegmatite with a strike length of more than 3 km. Its mineral reserve is unique grading 50% spodumene. This makes Greenbushes the highest-grade lithium mineral resource in the world at 2.8% Li₂O mineral reserves versus the 1.0-2.0% Li2O from other known hard rock unzoned pegmatites (mostly around 1.5% Li₂O).
Source: wiktionary