Commercial interest in the property was renewed when Mrose and Wappner (1959) discovered that sterrettite (kolbeckite) found there was actually a phosphate of the strategically important element scandium.
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).
Gonyer, misidentified an element, mistaking scandium for aluminum, hence the discreditation of the name sterrettite in favor of kolbeckite (Mrose and Wappner, 1969).
Kolbeckite occurs rarely in cavities in tan-colored crandallite from only one small area of the deposit, separated horizontally from the main zone of mineralization.
Kolbeckite ScP[O.sub.4] [multiplied by] 2[H.sub.2]O
Another rare mineral discovered quite by chance at the Flambeau mine is kolbeckite. Had it not been a sunny day, the reflection off the tiny crystal might have gone unnoticed.