Additionally, there was one well resolved band, peaked at 825-829 [cm.sup.-1], owing to the As-O stretching vibration of the As-O-Fe coordination of the ferric arsenate (i.e., scorodite
) and the surface complex (i.e., protonated Fe[O.sub.2]As(O)(OH) and unprotonated Fe[O.sub.2]As[(O).sup.2.sup.2-] forms) on the precipitates .
Overall, Sican and later pre-Hispanic metal mining in the Lambayeque region of the north coast of Peru was technically simple, labor intensive, and focused on readily accessible outcropped, weathered and enriched, high-grade oxide, carbonate and sulfide ore bodies bearing copper and arsenic (arsenopyrite and scorodite
It is known that scorodite
compounds are favorably formed in acidic solution of Fe (III) and As (V) at high temperature (eg.
The gossan is composed primarily of goethite, quartz (Si[O.sub.2]), beudantite (Pb[Fe.sub.3](As[O.sub.4]) (S[O.sub.4])[(OH).sub.6]), jarosite ((K,Na)[Fe.sub.3][(S[O.sub.4]).sub.2][(OH).sub.6]), plumbojarosite [(Pb[Fe.sub.6](S[O.sub.4]).sub.4][(OH).sub.12]), argentojarosite (Ag[Fe.sub.3][(S[O.sub.4]).sub.2][(OH).sub.6]), bindheimite ([Pb.sub.2][Sb.sub.2][O.sub.6] (O,OH)) and scorodite
with accessory cinnabar (HgS), native Ag, Au, and cassiterite (Sn[O.sub.2]) (Boyle 1995).
Looking around optimistically for a fresh lot of those fine scorodite
specimens from Hezhou, Guangxi Zhuang Autonomous Region (see the online "what's new" report of May 23, 2008), I was disappointed to find none such, although it should be noted that Marcus Origlieri of Mineral Zone still has a few excellent thumbnails from the original find; the very best of these, with sharp crystals to 1.5 cm, are priced just south of $1000.
The world's best specimens of paradamite and kottigite/parasymplesite have also been found there, as well as superb specimens of aurichalcite, scorodite
, hemimorphite, rosasite, wulfenite and other minerals.
Most exciting and promising, surely, among the what's-new items from this year's Dallas Show is a find of superb scorodite
in what is said to be a small prospect pit near the town of Hezhou, near the eastern border of Guangxi Zhuang Autonomous Region, southern China.
from "Tamdrost" (probably Oumlil, since 2001): highly lustrous, dark blue-green crystals to more than 2 cm.
Of these, Ernesto felt fairly confident in naming scorodite
, powellite, lotharmeyerite, and zincroselite, and he suspected that lavendulan, chalcophyllite and sainfeldite were present as well.
A total of several thousand mimetite specimens were recovered, as well as about 30 attractive specimens of scorodite
found later in 2003.
Albite Arsenopyrite Azurite Beryl Biotite Bismuth Calcite Cassiterite Chalcopyrite Danburite Dravite Ferberite Ferro-axinite Fluorapatite Fluorite Garnet (almandine?) Goethite Goyazite Hematite Malachite Molybdenite Monazite Muscovite Opal variety hyalite Plumbogummite Pyrite Quartz Rutile Scheelite Schorl Scorodite
Titanite Topaz Table 5.