according to Min. Rec. vol 26 ref., fervanite is "easily distinguished by its brown to yellow brown to pale green color" "most commonly as thin, botryoidal coatings on black kazakhstanite, however, may exhibit radiating clusters to 0.5 mm of distinct lath-like crystals"
Habit:
Laths to 0.5 mm
Colour:
brown to yellow brown to pale green
Quality for species:
Excellent - world class for species or very significant. (!!)
Gold Quarry Mine, Maggie Creek Mining Subdistrict, Carlin Trend, Eureka County, Nevada, USA