Kenoargentotetrahedrite-(Fe) is observed as greenish-grey anhedral grains, 50–150 μm in size, in association with galena, sphalerite and chalcopyrite in the Bajiazi Pb-Zn deposit of magmatic-hydrothermal type, Liaoning, China. The empirical formula from electron microprobe analyses is Ag_5.50Cu_4.17Fe_1.75Zn_0.31Sb_3.96As_0.04S_12.08, corresponding to the ideal formula Ag₆Cu₄Fe₂Sb₄S₁₂. The crystal structure of kenoargentotetrahedrite-(Fe) has been determined and refined by single-crystal X-ray diffraction with R₁ = 0.0192 for 1866 (404 unique) reflections. It is cubic, space group I$\overline{4}$3m with unit cell parameters a = 10.4928(2) Å, V = 1155.26(7) ų and Z = 2. The structure of kenoargentotetrahedrite-(Fe) is characterized by a poor occupancy of 0.05 of the octahedral S(2) site with the S(2)-M(2) bonding length of 1.9994(8) Å. The six Ag atoms at M(2) around S(2) form an octahedron cluster (Ag₆)⁴⁺ with the valence state of +4 and Ag-Ag distance of 2.8276(1) Å. The structure is identical to that by Rozhdestvenskaya et al., being composed of a collapsed sodalite-like framework of corner-connected M(1)S₄ tetrahedron forming cages containing M(2)₆-octahedron cluster, encircled by four SbS₃ trigonal pyramids. It is related to the tetrahedrite group minerals with the existence of the (Ag₆)⁴⁺ cluster replacing the S(2)-centered Ag₆ octahedron according to the substitution mechanism 6^M(2)Ag⁺ + ^S(2)S²⁻=^M(2)(Ag₆)⁴⁺ + ^S(2) S.

The new mineral, gysinite-(La), with the ideal formula PbLa(CO₃)₂(OH)⋅H₂O, has been discovered in lujavrite from the Saima alkaline complex, Liaoning Province, China. It commonly occurs as subhedral to anhedral, granular and platy crystals of 5 to 50 μm in size, in interstices or enclosed in microcline, aegirine and nepheline. Associated minerals include nepheline, aegirine, microcline, natrolite, eudialyte, lamprophyllite, bastnäsite-(Ce), parasite-(Ce), ancylite-(La), ancylite-(Ce), bobtraillite, britholite-(Ce), thorite, calcite and galena. The crystallisation of gysinite-(La) may be related to the post-magmatic carbonation event. Gysinite-(La) crystals are generally transparent, colourless, or pale yellow, with a vitreous lustre and white streak. It is brittle with an uneven fracture, and the estimated Mohs hardness is 3½ to 4. The calculated density is 5.007 g/cm³. Optically, gysinite-(La) is biaxial (–), α= 1.832(2), β= 1.849(4), γ = 1.862(5) in white light and 2V_meas = 81.6°. The empirical formula of gysinite-(La) is (La_0.93Pb_0.61Nd_0.23Pr_0.14Sr_0.04Gd_0.02Sm_0.01Eu_0.01Ca_0.01)_Σ2(CO₃)₂(OH)_1.34⋅0.66H₂O, which is calculated on the basis of general formula (REE_xM²⁺_2–x)(CO₃)₂(OH)_x⋅(2–x)H₂O. The strongest eight lines of its powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 5.596 (21) (011), 4.349 (100) (110), 3.732 (68) (111), 2.984 (61) (121), 2.667 (21) (031), 2.363 (48) (131), 2.090 (29) (221) and 2.028 (21) (212). Gysinite-(La) is orthorhombic, in the space group Pmcn, and unit-cell parameters refined from single-crystal X-ray diffraction data are: a = 5.0655(2) Å, b = 8.5990(3) Å, c = 7.3901(4) Å, V = 321.90(2) ų and Z = 2. It is a new member of the ancylite group and isostructural with gysinite-(Nd), but with La and Pb dominant in the metal cation sites in the structure.

Electron-microprobe and single-crystal X-ray-diffraction analyses have confirmed the second occurrence of felbertalite in the Funiushan copper skarn deposit, near Nanjing, in eastern China. It can be chemically described as Cu 2AgxPb6-2xBi8+x(S,Se)19, with a wide range of substitution of Bi + Ag for 2Pb, with x ranging from 0.64 to 1.03 (probably up to 1.33), suggesting the presence of a solid-solution series in felbertalite. The measured unit-cell parameters of a felbertalite grain with a compositi on of Cu2.20Ag0.70Pb4.65Bi8.45S19.12 are: a 27.68(4), b 4.046(1), c 20.67(3) Å, � 131.06(8)°, space group C2/m. A set of phases in the bismuthinite-aikinite series, mostly free of Ag and characterized by intermediate compositions between ideal formulae, were identified with electron-microprobe data. Compositional variations from Cu 1.80Pb1.80Bi2.20S6, through Cu1.53Pb1.53Bi2.47S6, Cu1.07Pb1.07Bi2.93S6, Cu0.73Pb0.73Bi3.27S6, to Cu0.58Pb0.58Bi3.42S6 within a single grain were observed, indicating that an intergrowth of three structural units, i.e., bismuthinite ribbons, krupkaite ribbons and aikinite ribbons, could occur in the progressive exsolution or precipitation of a single phase in the bismuthinite-aikinite series. The exceptionally high contents of Ag (0.76-1.27 wt%) i n the phase Cu0.83Ag0.10Pb0.90Bi3.13S6, presumably corresponding to krupkaite, are noted. Electron-microprobe analyses have also revealed the occurrence of a number of rare minerals, including junoite, unknown Cu 2AgxPb10-2xBi12+xS29 (1.23 < x < 1.49), berryite, benjaminite?, schirmerite?, Bi- and Ag-bearing galena, wittichenite and tetradymite. Within the intergrowths of Cu-Ag - Pb-Bi-S(Se,Te) minerals, Te (especially) and Se are preferably partitioned into Ag-bearing phases.

The crystal structure of bornite with ideal formula Cu₅FeS₄ from the Saishitang skarn copper deposit in Qinghai Province, along with bornite from the Yushui spouting hydrothermal copper deposit in Guangdong Province and the Bofang sandstone copper deposit in Hunan Province, has been refined by single-crystal X-ray diffraction with R1 = 0.0259–0.0483 (I > 2σ) and 0.0338–0.1067 for 2732 to 3273 unique reflections. As represented by the Saishitang sample, it is orthorhombic with a Pbca space group and unit cell parameters a = 10.97016(18) Å, b = 21.8803(4) Å, c = 10.9637(2) Å, V = 2631.61(8) Å3 and Z = 16. The structure is composed of sulfur layers parallel to the (0 1 0) lattice plane with interstices occupied by metal atoms. The Fe atoms occupy two tetrahedral sites with full occupancy, but the Cu atoms are all partially distributed over 20 paired sites, split from 10 sites with a distance ranging from 0.24 Å to 0.54 Å. The Fe-S tetrahedra are not split with Fe-S lengths from 2.2609 Å to 2.3286 Å (average 2.2997 Å). The Cu-S lengths in pyramidal triangles are from 2.218 Å to 2.397 Å (average 2.288 Å), whereas the Cu-S tetrahedra are strongly distorted, with great variations in Cu-S lengths from 2.224 Å to 2.604 Å (average 2.391 Å). The orthorhombic unit cell is stacked from 16 1a-type (5.5 Å) cubes; each cube has one tetrahedrally-coordinated Fe atom, five split from 3- to 4-coordinated Cu atoms, and two vacancies, i.e., 5Cu_III–IV+Fe_IV+2[]+4S. The phenomenon of site-splitting of Cu atoms may provide for a more accurate structure of bornite, allowing for a better understanding of its magnetic properties and ore-formation conditions.