The good correlation between W, Sb and As in soils from Sarzedas deposit is due to the weathering of ferberite
, stibnite and arsenopyrite from the mineralized veins and dykes, and precipitation of these elements in soils (Carvalho et al.
Then, from the Himalaya mine, just outside the city of La Paz, there was hubnerite, as loose, compound, bladed crystals from 5 to 12 cm, bright shiny black, with red flashes infrequently showing (these crystals have been verified as hubnerite, not ferberite
, and as such are a rarity for Bolivia).
I have seen crystals of aquamarine and ferberite
that have literally exploded in display cases when placed under hot lights.
Other aesthetic species have also been recovered, including fluorite, quartz, goethite pseudomorphs after siderite, and other important species such as cassiterite, ferberite
, metanovacekite, uranophane and metazeunerite.
Yet another Bolivian follow-up from last year: at Tucson in 2005, Mike Bergmann dazzled us with a couple of flats full of clusters of sharp, brilliant black, untwinned ferberite
crystals to 7 cm from the Tasna mine, Nor Chichas Province, Potosi Department.
Native bismuth, younger than bismuthinite and ferberite
, was occasionally found in the deeper levels.
Microcline is most commonly associated with quartz, topaz, needle-like schorl and, more rarely, ferberite
Ironically for this Year of China at the Main Show, there was almost nothing new in the way of Chinese minerals to be seen--although, of course, there were sterling specimens by the thousands of cinnabar, stibnite, ferberite
, fluorite, etc.
Fluorite in both purple and green crystals occurs in local abundance, often in association with well-developed, lustrous ferberite
Some of the minerals, including ferberite
, arsenopyrite, stannite and fluorite, are found in quartz veins, while others, including scheelite, chalcopyrite and bismuthinite, are found in the skarn.
In the prettiest pieces, all of thumbnail and miniature size, the little wurtzite plates perch up smartly on complex, sparkling, hillocky matrix consisting largely of bright chalcopyrite crystals to 2 mm and milky white, lenticular calcite crystals to about the same size; however, Jensen reports that microcrystals of about ten other species are present in specimens which he examined, these other associations including quartz, muscovite, arsenopyrite, ferberite
, sphalerite, galena and cassiterite.
Witness, this year, the new blue Romanian scheelite, the Spanish torbernite, the Bolivian bournonite and ferberite
, the new Imperial topaz from Zambia, the lilac gem scapolite from Afghanistan .