Chrysocollas

Ferripyrophyllite and related Fe3+-rich 2:1 clays in Recent deposits of Atlantis II Deep, Red Sea

“…Stretching absorption bands allow distinction of these clays from nontronite for which the Fe3+2(OH) band is at 3570 cm -1 (Goodman et al, 1976). The spectra are different from those of ferripyrophyllite given by Chukhrov et al (1979a,b) in which the OH-stretching and bending vibrations are observed at 3590 and 800 cm 1, respectively (842 cm -1 in Chukhrov et al, 1979b).…”

Transmission Electron Microscopy of Synthetic 2- and 6-Line Ferrihydrite

“…We follow this convention; however, only synthetic 6LFh samples are strictly consistent with the International Mineralogical Association definition (Fleischer et al, 1975;Farmer, 1992). Other commonly used names for ferrihydrite include "protoferrihydrite" (the name originally proposed for 2LFh), "amorphous ferric oxide," and "hydrous ferric oxide" (e.g., Chukhrov et al, 1973;Towe and Bradley, 1976;Farmer, 1992;Manceau et al, 1995).…”

“…Fefrihydrite is a common iron oxide mineral in lowtemperature surface environments such as soils, lakebottom sediments, drainage ditches, and hot-and coldspring deposits (e.g., Chukhrov et al, 1973;Schwertmann and Fischer, 1973;Childs et al, 1986;Schwertmann et al,, 1987;Schwertmann, 1988;Schwertmann and Taylor, 1989). Because of its small grain size (<--6 nm) and large surface area (hundreds of square meters per gram), even small amounts of ferrihydrite can have important consequences for many soil properties (Cornell and Schwertmann, 1996;Jambor and Dutrizac, 1998;Childs, 1992).…”

“…Ferrihydrite also occurs as an aqueous alteration product in meteorites (Li et al, 1999;Brearley, 1997;Lee et al, 1996), and it is an important corrosion product of iron and steel. Naturally occurring ferrihydrite can be formed by biological processes (e.g., Chukhrov et al, 1973;Schwertmann and Fischer, 1973;Konhauser, 1997).…”

Thermogravimetric analysis, PXRD, EDX and XPS study of chrysocolla (Cu,Al)2H2Si2O5(OH)4·nH2O-structural implications

“…Chukhrov and Anosov [9] reported the thermal curve for chrysocolla 4 which shows characteristic endothermal effects at 120-140, 450-530, and 690-700°, and an exothermic reaction at 1040°, with a typical montmorillonite character. Chukhrov et al [10] reported the DTA patterns of some seven chrysocolla mineral samples from Russia.…”