Pyrite, the most abundant of the Emperor mine metallic minerals, occurs as minute grains and disseminations, as microcrystals in vein like aggregates, and as small crystals and clusters in the interstices between bladed sylvanite crystals.
Sylvanite is the principal telluride mineral at the Emperor mine, and occurs in a range of associations, intergrown on a fine scale with pyrite, tetrahedrite, arsenopyrite, hessite, native tellurium and occasionally gold.
These include apple-green emmonsite, and a vanadium-rich variety of the rare scandium phosphate kolbeckite in tiny lime-green crystals associated with sylvanite.
He suspected that the ore samples in the store window were sylvanite, a gold-silver telluride first described in Romania but relatively unknown to American assayers.
With the help of John Harnan, Burns and Doyle found a rich sylvanite vein, which they eventually named the Portland vein.
Stage II includes deposition of milky to smoky quartz, pale purple fluorite, fine-grained pyrite, specular hematite, dolomite or ankerite, celestine, barite, roscoelite, sphalerite, galena, tetrahedrite, calaverite, krennerite, sylvanite, petzite, hessite, and native gold.
In the past, a common practice was to call yellowish telluride minerals calaverite and to call silvery tellurides sylvanite.
Krennerite occurs in the vein deposits as small, vertically striated silver-white to pale brass-yellow prisms that commonly have been misidentified as sylvanite or calaverite.
Nagyagite coated by altaite is reported to form zones around sylvanite crystals (Stumpfl, 1970, Eckel, 1997).