1997) mention that pseudomorphs of sphalerite, tetrahedrite and even gratonite
after galena are known from the locality.
If you had the means, you could take home from Denver a simply smashing 19th-century Philly specimen of such things as Utah cuprotungstite, Peruvian gratonite
, German kermesite, pre-Bolshevik Russian gem crystals and other historical treasures.
The best gratonite
specimen we ever saw came from this collection.
It is characterized by sphalerite and galena, along with pyrite, chalcopyrite, tetrahedrite-tennantite, marcasite, arsenopyrite and gratonite.
The galena in the Lead-Zinc Zone is occasionally found partly replaced by gratonite.
Alabandite (*)Apatite Arsenic (*)Pb-As-S glass (*)Barite (*)Baumhauerite-2a (*)Bournonite (*)Calcite (*)Chalcopyrite Chatkalite Clinozoisite Geocronite Gratonite (*)Hutchinsonite Jamesonite Manganaxinite Marcas ire (*)Orpiment Realgar Robinsonite (*)Scheelite Seligmannite Stannite (*)Wurtzite
Assemblages include: pyrite-hematite-realgar associated with high-silver mineralization consisting of a complex association which includes gratonite, baumhauerite, aramayoite, "waxy" sphalerite, and galena (Ward, 1961); and alunite-native sulfur rug fillings in enargite-pyrite pipes (Cerro de Pasco Corporation, 1950).
Cerro de Pasco is the type locality for gratonite (Palache and Fisher, 1940), and has produced the world's best specimens.
Crystals of gratonite on the type specimens are dark lead-gray and up to 1 x 1.
Fine native copper, large barite crystals, gratonite crystals, spectacular formations of post-mining sulfates, and the world's finest voltaite are among the features of this historic deposit.
The deeper, unaltered portions of the orebodies are occasionally crossed by thin veins containing sulfides and sulfosalts including sphalerite, galena, tetrahedrite and gratonite.
The gratonite forms carpets and druses on massive pyrite, as steel-gray prismatic crystals with three-faced rhombohedral terminations.