Abstract: Belogubite CuZn(SO₄)₂ ⋅ 10H₂O, a new mineral of the chalcanthite group, is found in the Gai (Gaiskoe) massive sulfide deposit, South Urals, Russia. This mineral forms aggregates of blue grains up to 1 mm. It is optically biaxial (–), n_p = 1.512(2), n_m = 1.525(2), n_g = 1.531(2), 2V = 70(10)°. The chemical composition of the holotype sample is as follows (wt %): 1.12 MgO, 0.10 MnO, 3.15 FeO, 8.98 CuO, 18.02 ZnO, 32.49 SO₃, and 36.75 H₂O, total 100.61. The empirical formula is (Cu_0.55Zn_0.45)_Σ1.00(Zn_0.64Fe_0.22Mg_0.14Mn_0.01)_Σ1.01S_1.99O_7.98 ⋅ 10.02H₂O. The crystal structure of belogubite is studied using the single crystal method, R = 0.016. The mineral is triclinic, (Formula presented.) The unit cell parameters are: a = 6.2548(1), b = 10.6112(2), c = 6.0439(1) Å, α = 82.587(1), β = 109.625(1), γ = 104.848(1)°, V = 364.81(1) ų, and Z = 1. The strongest reflections of the powder XRD pattern [d_meas., Å (I, %) (hkl) are: 5.73 (35) (100), 5.576 (47) (–110), 4.873 (100) (–111), 3.907 (31) (021), 3.719 (45) (0 –21), 3.229 (27) (111), 2.915 (25) (–221), and 2.684 (26) (130).