Wer's ganz genau wissen will, dem kann ich folgende Artikel von 1996 und 1985 empfehlen:
Rager et al. (1996): Color, crystal chemistry, and mineral association of a green sphalerite from Steinperf, Dill syncline, FRG. European Journal of Mineralogy 8, 1191-1198.
Das Abstract:
Green sphalerite and the coexisting minerals calcite and prehnite occur in small veins in a basalt of Steinperf, Dill Syncline, Germany. Chem. anal. by AAS and electron microprobe reveal that all 3 minerals are almost pure end members and contain only minor amts. of the transition elements. Small amts. of Co2+(80 ppm) in the tetrahedral Zn sites cause the green color of this particular sphalerite. EPR studies of the specimen reveal that the cubic Zn positions are distorted by the incorporation of the Jahn Teller ion Co2+ without affecting the overall crystal structure. The minerals formed under hydrothermal conditions, starting with calcite and followed by prehnite, which crystd. under oxidizing conditions as indicated by the incorporation of Fe3+. Sphalerite formed under more reducing conditions as the last mineral in the sequence and incorporated all cobalt as Co2+.
Henn, U. & Hofmann, C. (1985): Green sphalerite from Zaire. Journal of Gemmology 19, 416-418.
Abs.:
The dark-green color of sphalerite from Kipushi, Zaire, is the result of trace contents of Co (744.2 ppm), which shows a absorption max. at 670 nm in the sphalerite spectrum. This absorption max is the result of an 4A2 -> 4T1(P) transition of Co2+ in the tetrahedral crystal field of sphalerite.
Thema: grüner Sphalerit (Gelesen 9833 mal)
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