New discoveries of kuksite, Pb3Zn3Te6+P2O14, from the Black Pine mine, Montana, and Blue Bell claims, California, have enabled a detailed crystal-chemical study of the mineral to be undertaken. Single-crystal X-ray structure refinements of the structure indicate that it is isostructural with dugganite, Pb3Zn3Te6+As2O14, and joëlbruggerite, Pb3Zn3(Sb5+,Te6+)As2O13(OH,O). Kuksite from the Black Pine mine crystallizes in space group P321, with unit-cell dimensions a = 8.392(1), c = 5.204(1) Å, V = 317.39(8) Å3, and Z = 1 (R1 = 2.91% for 588 reflections [Fo > 4σF] and 3.27% for all 624 reflections), while Blue Bell kuksite has the unit cell a = 8.3942(5), c = 5.1847(4) Å, and V = 316.38(4) Å3 (R1 = 3.33% for 443 reflections [Fo > 4σF] and 3.73% for all 483 reflections). Chemical analyses indicate that solid-solution series exist between kuksite, dugganite, and joëlbruggerite. Raman spectroscopic and powder X-ray diffraction data are also presented for samples from both occurrences.
The crystal structure of the chemically related species yafsoanite, (Ca,Pb)3Te26+Zn3O12, from the type locality (Delbe orebody, Kuranakh Au Deposit, Aldan Shield, Saha Republic, Russia), has been refined to R1 = 2.41% for 135 reflections [Fo > 4σF] and 3.68% for all 193 reflections. A garnet-type structure has been confirmed and significantly improves upon the results of an earlier structure determination.