The mine is also the type locality for the phosphates englishite, gordonite, millisite, montgomeryite, overite and wardite.
Millis is frustrating considering that he is the discoverer of the deposit, and that the mineral millisite was later named in his honor (Larsen and Shannon, 1930) and remains a valid species.
Larsen (1942b) made a detailed study of the paragenetic relationships in the evolution of variscite nodules in the Clay Canyon deposit, identifying six stages: (1) variscite formation, followed by fracturing and the introduction of thin black quartz veinlets; (2) banded minerals, primarily crandallite, millisite and wardite, replacing and enclosing variscite while opening up cavities through shrinkage (some variscite nodules were entirely replaced by crandallite); (3) formation of free-growing crystals of gordonite, englishite, montgomeryite and probably overite and kolbeckite in cavities; (4) a minor reversion to crandallite formation from solution as isolated oolites; (5) apatite-group minerals; and finally (6) the limonitic phase (limonite is not present inside any of the nodules).
Millisite (NaK)Ca[Al.sub.6][([PO.sub.4]).sub.4][(OH).sub.9] 3[H.sub.2]O
Millisite was described as a new species from Clay Canyon by Larsen and Shannon (1930); they named it after F.
Research in south-western Australia has shown that all types of phosphate rock fertilisers (crandalite millisite
phosphate rocks, low and highly reactive apatite phosphate rocks) are poorly effective relative to superphosphate for most soils, environments, and crop and pasture species in south-western Australia (Bolland et al.