Assessing lithium brine and clay assays First, Hickson wrote about sediment samples:
It actually depends on the area and whether we are talking about brines or sediment samples. Many high numbers (i.e., > 400 ppm) are common in sediment samples from the playas in Nevada. Mostly this is Li that is bound up in hectorite and other types of clay and evaporitic minerals. These types of minerals have proven difficult from an extraction perspective (see for example the work of Western Lithium (now Lithium Americas (TSX:LAC)) on their King’s Valley property. These lithium rich clays do have other uses, such as “muds” in drilling applications such as oil wells.