Visible silver minerals such as proustite
and pyrargyrite are common.
Sum-frequency mixing of CO2 and He-Ne lasers in proustite
// Optics Letters.--February, 1982.--Vol.
And, as fairly frequently at the Denver Show, Denver resident Ralph Clark put in a case of selections from his fabulous thumbnail collection--with the Montana veszelyite, Tsumeb mimetite, Chilean proustite
, Swiss anatase, etc., etc., of one's dreams.
Most environmental arsenic occurs naturally, appearing in deposits of minerals and ores including arsenopyrite, enargite, and proustite
. A smaller but still significant source of arsenic exposure is anthropogenic.
But I still would have preferred to see a larger proportion of higher quality specimens: these books are, after all, addressed to the collector, and if we collectors are to be reminded that there is more to the world of beautiful minerals than gold, proustite
, azurite, rhodochrosite and tourmaline, we need to see some specimens of rock-forming minerals performing at their peaks.
Similar pearceite specimens have trickled out before from the huge silver mine, but these new pieces display very brilliant rosettes, some with attachments of bright red, pinwheel-shaped aggregates of what is probably proustite
(Luis's labels call it pyrargyrite, but proustite
seems more likely, as the Uchucchacua orebody is arsenic-heavy, and the association here is with As-rich pearceite, not Sb-rich polybasite).
crystals are well known for changing from a beautiful transparent red color to black.
And I and my fellow thumbnail collectors are always delighted when Ralph Clark puts in a case of his best; at this show we saw 30 of Ralph's most incredibly fine thumbnails, and maybe if I mention particularly his Swiss anatase, Montana veszelyite, Australian chalcocite, Chilean proustite
and South African rhodochrosite, he will someday trade me one of them for my very best Herkimer diamond ...
The Crown Crescent lode in the Emperor mine has yielded very minor amounts of bournonite, pyrargyrite, proustite