Ronpetersonite, BaWO (super 4) , the barium analogue of scheelite, a new mineral from the Gun Occurrence in the Yukon, Canada

Ronpetersonite, BaWO (sub 4) , is a new mineral from the Gun occurrence in the Yukon, Canada, where it is found in aggregates up to 500 mu m in diameter in a groundmass comprised of witherite, cerchiaraite-(Al), and edingtonite. Grains of ronpetersonite are heavily included and anhedral. Crystals are colorless and transparent with a vitreous luster and white streak. Fracture and cleavage could not be determined. The calculated density is 6.363 g/cm (super 3) based on the empirical formula. The empirical formula calculated on the basis of electron probe microanalysis (n = 11) is Ba (sub 1.00) W (sub 1.00) O (sub 4) . Ronpetersonite is tetragonal, I4 (sub 1) /a (space group 88), a = 5.6192(4) Aa, b = 5.6192(4) Aa, c = 12.7348(11) Aa, alpha = 90.0(0) degrees , beta = 90.0(0) degrees , gamma = 90.0(0) degrees , V = 402.11(6) Aa (super 3) , Z = 4. The crystal structure [R (sub 1) = 1.2% for 400 reflections with F (sub o) > 4sigma (F (sub o) ) and R (sub 1) = 1.8% for all 491 unique reflections] shows ronpetersonite to be the Ba-analogue of scheelite. The mineral is named in honor of Emeritus Professor Dr. Ronald C. Peterson of Queen's University for his important contributions to mineralogy, especially the mineralogy of mine wastes, sulfate minerals, and the mineralogy of Mars.