Abstract: The strongest lines in the X-ray powder diffraction pattern of type material of glaucocerinite from Laurion (Greece), indexed on a hexagonal pseudocell, are 10.9 (100) (003), 5.45 (90) (006), 3.63 (80) (009), 2.62 (60) (012), 2.46 (60) (015), 2.231 (50) (018), and 1.981 Å (50) (0.1.11). The pseudocell parameters are a 3.0700(8), c 32.65(1) Å. Chemical analysis of topotype material yields the formula [(Zn,Cu)₅Al₃(OH)₁₆] [(SO₄)_1.5·9H₂O] based on a pyroaurite-like structure. The pseudocell parameters for this sample are a 3.057(3), c 32.52(5) Å. Optical data are 2V_α ⋍ 60°, α 1.540, β 1.554, γ 1.562; D(meas.) = 2.4±0.1 g/cm³, D(calc.) = 2.33 g/cm³. So-called ‘woodwardite’ from Caernarvonshire, Wales, is identified as the Cuanalogue of glaucocerinite. An ‘11 Å mineral’ occurring together with carrboydite in Western Australia is shown to be the Ni-analogue of glaucocerinite. Alleged cotype glaucocerinite from Laurion is related to woodwardite and has the formula [(Zn,Cu)₂Al(OH)₆][(SO₄)_0.5 · 3H₂O]. This is a cation-ordered pyroaurite-type structure with hexagonal cell parameters a 5.306(2), c 26.77(2) Å. The strongest X-ray powder lines occur at 8.9 (100) (003), 4.47 (90) (006), 2.55 (60) (113), and 2.28 Å (50) (116).