The new mineral isselite, Cu6(SO4)(OH)10(H2O)4⋅H2O, has been discovered in the Lagoscuro mine, Monte Ramazzo mining complex, Genoa, Eastern Liguria, Italy. It occurs as sprays of blue acicular crystals, up to 0.1 mm long, associated with brochantite and posnjakite. Streak is light blue and the lustre is vitreous. Isselite is brittle, with irregular fracture and good cleavage on {001} and {100}. Measured density is 3.00(2) g/cm3. Isselite is optically biaxial (–), with α = 1.599(2), β = 1.633(2) and γ = 1.647(2) (determined in white light). The measured 2V is 63.6(5)°. Dispersion is moderate, with r > v. The optical orientation is X = b, Y = c and Z = a. Isselite is pleochroic, with X = light blue, Y = blue, Z = blue; X << Z < Y. Electron microprobe analyses give (wt.%): SO3 11.45(21), MgO 0.31(7), CoO 1.07(14), NiO 9.41(90), CuO 51.29(126), ZnO 1.10(20), H2Ocalc 24.21, total 98.84. The empirical formula of isselite, based on Σ(Mg,Co,Ni,Cu,Zn) = 6 atoms per formula unit, is (Cu4.80Ni0.94Co0.11Zn0.10Mg0.06)Σ6.00(S1.06O4.19)(OH)10⋅5H2O. Isselite is orthorhombic, space group Pmn21, with unit-cell parameters a = 6.8070(14), b = 5.8970(12), c = 20.653(4) Å, V = 829.0(3) Å3 and Z = 2. The crystal structure of isselite was refined from single-crystal X-ray diffraction data to R1 = 0.067 on the basis of 2964 reflections with Fo > 4σ(Fo). It shows a layered structure formed by zig-zag {001} layers of Cu-centred polyhedra. Sulfate groups occur in the interlayer along with one H2O group. Isselite is chemically related to redgillite and montetrisaite.

新的矿物isselite，铜6（SO 4）（OH）10（H 2 O）4 ⋅H 2 O，已经在Lagoscuro矿被发现，蒙Ramazzo挖掘复杂，热那亚，东方利古里亚，意大利。它以蓝色针状晶体喷雾的形式出现，最长可达0.1毫米，与青铜矿和posnjakite有关。条纹为浅蓝色，光泽为玻璃态。Isselite易碎，在{001}和{100}上具有不规则的断裂和良好的裂解。测得的密度为3.00（2）g / cm 3。Isselite是光学双轴（–），α= 1.599（2），β= 1.633（2）和γ= 1.647（2）（由白光确定）。测得的2V为63.6（5）°。色散适中，r > v。光学取向为X = b，Y = c和Z = a。Isselite是多色的，X =浅蓝色，Y =蓝色，Z =蓝色；X << Z < Y。电子探针分析得出（wt。％）：SO 3 11.45（21），MgO 0.31（7），CoO 1.07（14），NiO 9.41（90），CuO 51.29（126），ZnO 1.10（20），H 2 O计算24.21，总计98.84。基于Σ（Mg，Co，Ni，Cu，Zn）= 6个原子/每个公式单元的isselite的经验公式为（Cu 4.80 Ni 0.94 Co0.11的Zn 0.10 Mg的0.06）Σ6.00（š 1.06 ø 4.19）（OH）10 ⋅5H 2 O. Isselite是斜方晶系，空间群Pmn的2 1，具有晶胞参数一个= 6.8070（14），b = 5.8970（ 12），C ^ = 20.653（4），V = 829.0（3）3和ž = 2 isselite的晶体结构从单晶X射线衍射数据细化到- [R 1 = 0.067的2964的基础上与反射˚F ö >4σ（˚Fo）。它显示了由以铜为中心的多面体的之字形{001}层形成的分层结构。硫酸根与一个H 2 O基团一起出现在中间层中。Isselite在化学上与赤铁矿和蒙脱石有关。