Summary: Drugmanite occurs as rare colourless transparent platy crystals, up to 0.2 mm, aggregated in bunches, in vugs of a mineralized and silicified limestone. Hardness < 6. Crystals monoclinic, forms {001} {110}, parameters from indexed X-ray powder pattern (and monocrystal measurements): a = 11.110 (11.111) Å, b = 7.976 (7.986), c = 4.644 (4.643), β = 90°18′ (90°.41°). Space group P2₁/a with Z = 2 giving D_calc = 5.55. Strongest lines are 4.63 Å (9), 3.752 (IO), 3.350 (8), 3.247 (8), 2.912 (9). Mean refractive index 1.88 from reflectance measurements. Strong dispersion r < v, optic axial plane // (olo), 2V_α = 33±2°. Electron microprobe analysis gave P 8.89, Al 0.85, Fe 6.19, Pb 59.76%, leading to Pb4.02(Fe1.553+Al0.45)P4.00O17.02·3H2O or Pb2(Fe0.783+Al0.22)(PO4)2(OH)·H2O. Associated minerals are pyromorphite, anglesite, corkite and phosphosiderite. Named for J. Drugman, Belgian mineralogist (1875–1950).