Stangersite, a new tin germanium sulfide, from the Kateřina mine, Radvanice near Trutnov, Czech Republic

Abstract

The new mineral stangersite was found in the burning waste dump of abandoned Kateřina coal mine at Radvanice near Trutnov, northern Bohemia, Czech Republic. The new mineral occurs as well-formed, flattened, acicular crystals with a cross-section of 2-5 × 20-40 μm and up to 1 cm in length. They constitute random or fan-shaped clusters on rock fragments and on crumbly black ash in association with greenockite, herzenbergite, unnamed GeS 2 and GeAsS. Stangersite was also observed as irregular grains, up to 100 μm in size, in the multicomponent aggregates on which the above-described crystals grow. These aggregates are formed, beside stangersite, by minerals of Bi-Sb, Bi 2 S 3-Sb 2 S 3 and Bi 2 S 3-Bi 2 Se 3 solid solutions, Bi 3 S 2 , Bi-sulfo/seleno/tellurides, tellurium, unnamed PbGeS 3 , Cd 4 GeS 6 , GeAsS, GeS 2 , Sn 5 Sb 3 S 7 , greenockite, cadmoindite, herzenbergite, teallite and Sn-and/or Se-bearing galena. Stangersite formed under reducing conditions by direct crystallization from hot gasses (250-350 °C) containing Cl and F, at a depth of 30-60 cm under the surface of the dump. The mine dump fire started spontaneously and no anthropogenic material was deposited there. Stangersite is brittle (aggregates) or elastic, to flexible (acicular crystals). It is orange to yellowish red with a very light yellowish brown streak, translucent to transparent in transmitted light, and has vitreous to adamantine luster. Cleavage is perfect in two directions: perpendicular and oblique to elongation of crystals. The VHN microhardness is 55 kp•mm-2 (539 MPa) and corresponds to Mohs hardness about 2; the calculated density is 3.98 g•cm-3. In the reflected light, stangersite is light greyish white. Bireflectance and pleochroism were not observed due to distinct orange-brown internal reflections. Anisotropy under crossed polars is strong with dark brownish grey to reddish-brown or brownish violet rotation tints. The empirical formula, based on electron-microprobe analyses of acicular crystals of stangersite, is Sn 1.02 Ge 0.94 (S 2.93 Se 0.10) Σ3.03. The ideal formula is SnGeS 3 , which requires Sn 41.29, Ge 25.25, S 33.46, total 100 wt. %. The chemical composition of stangersite from multicomponent aggregates shows an extensive PbSn-1 substitution covering nearly the whole field of stangersite in the SnGeS 3-PbGeS 3 solid solution. Stangersite is monoclinic, P2 1 /c, a = 7.2704(15), b = 10.197(2), c = 6.8463(14) Å, β = 105.34(3)º, with V = 489.5 Å 3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d, Å/I(hkl)] are: 7.006/100(100), 4.135/49(120), 3.077/47(130), 2.776/38(022), 2.699/69(211), 2.1213/31(320), and 1.7239/35(41-2; 410). Stangersite has a layered structure, with corrugated (100) layers of Sn 2+ S 5 coordination pyramids and with interspaces filled by lone electron pairs of Sn 2+ and [001] chains of Ge 4+ S 4 coordination tetrahedra. The Raman spectrum of stangersite with tentative band assignments is given. We named the mineral after its chemical constituents: Sn (stannum), Ge (germanium) ...

Radvaniceite, GeS2, a New Germanium Sulphide, from the Kateřina Mine, Radvanice near Trutnov, Czech Republic

“…Two types of radvaniceite were observed in the studied material. The first comprised rich groups of fibres in association with stangersite [20], herzenbergite, greenockite, and members of Bi-Sb solid solutions. The second type represents irregular radvaniceite grains in the earlier multicomponent aggregates on which the above described fibres grow.…”

“…[17]) allows the proposal of this new mineral. Radvaniceite is named after its type locality Radvanice, one of the past centres of coal mining in the Czech limb of the Intra-Sudetic Basin, and a unique locality worldwide with respect to the number and quantity of metaland metalloid-bearing sublimates [14,15,[18][19][20][21]. The new mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (number 2021-052).…”

Pertoldite, trigonal GeO2, the germanium analog of α-quartz: a new mineral from Radvanice, Czech Republic

“…Pertoldite holotype sample was found in 1996 in "fumarole" in the central part of a burning dump of abandoned Kateřina coal mine (GPS: 50°33'39.0" N 16°03'56.2" E), situated at the eastern edge of the Radvanice village, about 12 km east of the town of Trutnov in Hradec Králové region, the Czech Republic. Radvanice is known worldwide as a unique locality with respect to the quantity and number of metal-and metalloid-bearing sublimates (Žáček and Ondruš 1997a;Žáček and Skála 2015;Sejkora et al 2020Sejkora et al , 2022 including radioactive galena described by Čurda et al (2017). From a regional geology viewpoint, the area forms a part of the Czech limb of the Intra-Sudetic Basin, which comprises continental siliciclastic sediments from early Mississippian (Namurian C) to the early Triassic age (Tásler et al 1979).…”