Publication details
Chukotkaite, AgPb7Sb5S15, a new sulfosalt mineral from Eastern Chukotka, Russia
| Authors | |
|---|---|
| Year of publication | 2020 |
| Type | Article in Periodical |
| Magazine / Source | The Canadian Mineralogist |
| MU Faculty or unit | |
| Citation | |
| Web | https://doi.org/10.3749/canmin.2000036 |
| Doi | http://dx.doi.org/10.3749/canmin.2000036 |
| Keywords | chukotkaite; rod-based sulfosalt; new mineral; crystal structure; Iultin District; Chukotka |
| Description | The new sulfosalt chukotkaite, ideally AgPb7Sb5S15, was discovered in the valley of the Levyi Vulvyveem river, Amguema river basin, Iultin District, Eastern Chukotka, Chukotka Autonomous Okrug, North-Eastern region, Russia. The new mineral forms anhedral grains up to 0.4 x 0.5 mm intergrown with pyrrhotite, sphalerite, galena, stannite, quartz, and Mn-Fe-bearing clinochlore. Other associated minerals include arsenopyrite, benavidesite, diaphorite, jamesonite, owyheeite, uchucchacuaite, cassiterite, and fluorapatite. Chukotkaite is lead-grey and has metallic luster and a grey streak. It is brittle and has an uneven fracture. Neither cleavage nor parting were observed. Mohs hardness is 2-21/2. D-calc. = 6.255 g/cm(3). In reflected light, chukotkaite is white, moderately anisotropic with rotation tints varying from bluish-grey to brownish-grey. No pleochroism or internal reflections are observed. The chemical composition of chukotkaite is (wt.%; electron microprobe) Ag 3.83, Pb 53.67, Sb 24.30, S 18.46, total 100.26. The empirical formula based on the sum of all atoms = 28 pfu is Ag0.93Pb6.78Sb5.22S15.07. Chukotkaite is monoclinic, space group P2(1)/c, a = 4.0575(3), b = 35.9502(11), c = 19.2215(19) angstrom, beta = 90.525(8)degrees, V = 2803.7(4) angstrom(3), and Z = 4. The strongest lines of the powder X-ray diffraction pattern [d, angstrom (I, %) (hkl)] are: 3.52 (100) (045), 3.38 (50) (055), 3.13 (50) (065), 2.96 (30) ((1) over bar 44), 2.82 (25) (066), 1.91 (50) (0 1 10). The crystal structure of chukotkaite was refined from single-crystal X-ray diffraction data to R = 0.0712 for 3307 observed reflections with I-obs > 3 sigma(I). Chukotkaite belongs to the group of rod-based sulfosalts. The new mineral is named after the region of its type locality: Chukotka Autonomous Okrug, North-Eastern Region, Russia. |