Paulmooreite is a new lead arsenite, Pb2As2O5, from Långban, Värmland, Sweden. It was known in the Flink lists as #305 and #49. The new mineral is monoclinic, P21 with a = 8.558(5), b = 5.654(3), с = 13.606(8)A, β = 108.88(5)°. The strongest lines in the X-ray diffraction pattern are 3.30 100 212 or 210, 2.761 80 021, 2.905 80 114, 1.766 70 325 or 126, and 3.02 70 213 or 202. Paulmooreite is colorless to light orange. The mineral has complex morphology; crystals are tabular either on {001} or {100}. The forms present are {100}, {001}, {011}, {102}, {110}, and {111}. There is one perfect cleavage, {001}. The density is 6.95 (meas), 6.86 (calc) g/cm3. The hardness is approximately 3 (Mohs). Optically, paulmooreite is biaxial positive with 2Vz = 65(5)°. The refractive indices are greater than 1.9, Y is parallel to b, Zc = 10(1)°. The mineral occurs as euhedral crystals in vugs with green andradite and as colorless crystals on fracture surfaces.

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