Teallite from Radvanice near Trutnov (Czech Republic)
Sejkora, J.; Berlepsch, P.; Makovicky, E.; Balić-Žunić, T.; Litochleb, J.
published: May 8, 2002
ArtNo. ESP154017702003, Price: 29.00 €
Teallite, orthorhombic PbSnS2, was found at a burning coal mine dump of the Kateřina mine at Radvanice near Trutnov, Czech Republic in close association with "GAF" phase (greenockite, anhydrite and fluorite pseudomorphoses after an unknown high temperature Cd-Ca-S-F mineral), greenockite, Sn, Se containing galena, antimonian bismuth and bismuthinite. Three types of teallite occurrences are distinguished based upon morphology, chemistry and mineral association. Teallite A forms greyish black platy crystals up to 0.6 mm in size, it is a relatively Pb-poor member with 42-47 mol.% Pb in cation position and contains about 7 mol.% Se in anion position, its empirical formula (48 point analyses) was calculates as Pb0.89Sn1.11(S1.85Se0.15)Î£2.00. In reflected light it is white with light yellowish tint, weak pleochroism; anisotropic rotation tints are from light to dark grey; VHN5 g microhardness is 53 kp/mm2 (520 MPa). The results of crystal structure determination from single crystal X-ray diffraction data (R1 = 3.86 % with Fo > 4Ï[Fo]) are given for different refinements models. Teallite B occurs as platy crystals up to 0.2 mm partly intergrown with galena or in form of aggregates in greenockite, its 48-54 mol.% Pb in cation position is close to the ideal composition PbSnS2. It has about 7 mol.% Se in anion position. The empirical formula Pb1.01Sn0.99Sb0.01Bi0.01(S1.86Se0.13)Î£1.99 was calculated from 16 point analyses. Teallite C forms irregular grains in greenockite or marginal parts of crystals of teallite A. Its composition is similar to teallite B, but it contains minor Cd and its Se contents is in the range 10-13 mol.%. It has an empirical formula Pb1.01 Sn0.98Cd0.01 (S1.77Se0.23)Î£2.00 (4 point analyses).