Petrovite, Na10CaCu2(SO4)8, is a new sulfate mineral discovered on the Second scoria cone of the Great Tolbachik fissure eruption. The mineral occurs as globular aggregates of tabular crystals up to 0.2 mm in maximal dimension, generally with gaseous inclusions. The empirical formula calculated on the basis of O = 32 is Na6(Na1.80K0.20)Σ2Na(Ca0.82Na0.06Mg0.02)Σ0.90(Cu1.84Mg0.16)Σ2(Na0.52□0.48)Σ1S8.12O32. The crystal-chemical formula is CuNa6−2xCax(SO4)4, which, for x ≈ 0.5, results in the idealised formula Na10CaCu2(SO4)8. The crystal structure of petrovite was determined using single-crystal X-ray diffraction data; the space group is P21/c, a = 12.6346(8), b = 9.0760(6), c = 12.7560(8) Å, β = 108.75(9)°, V = 1385.1(3) Å3, Z = 2 and R1 = 0.051. There are one Cu and six Na sites, one of which is also occupied by the essential amount of Ca. The Cu atom forms five Cu–O bonds in the range 1.980–2.180 Å and two long bonds ≈ 2.9 Å resulting in the formation of the CuO7 polyhedra, which share corners with SO4 tetrahedra to form isolated [Cu2(SO4)8]12− clusters. The clusters are surrounded by Na sites, which provide their linkage into a three-dimensional framework. The Mohs’ hardness is 4. The mineral is biaxial (+), with α = 1.498(3), βcalc = 1.500, γ = 1.516(3) and 2V = 20(10) (λ = 589 nm). The seven strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 7.21(27)(110); 6.25(38)(102); 4.47(31)(212); 3.95(21)(30 $\bar{2}$ ); 3.85(17)(121); 3.70(36)(202); and 3.65(34)(22 $\bar{1}$ ). The mineral is named in honour of Prof Dr Tomas Georgievich Petrov (b. 1931) for his contributions to mineralogy and crystallography and, in particular, for the development of technology for the industrial fabrication of jewellery malachite.

沸石Na 10 CaCu 2（SO 4）8是一种新的硫酸盐矿物，发现于大Tolbachik裂隙喷发的第二碎屑锥上。矿物以最大尺寸最大为0.2 mm的板状晶体的球状聚集体形式存在，通常带有气态夹杂物。经验式O的基础上计算= 32为Na 6（钠1.80 ķ 0.20）Σ2钠（钙0.82钠0.06的Mg 0.02）Σ0.90（铜1.84的Mg 0.16）Σ2（钠0.52 □ 0.48）Σ1 š 8.12 Ò 32。晶体化学式为CUNA 6-2 X的Ca X（SO 4）4，其中对于X ≈0.5，结果理想化式IIa在10 CaCu 2（SO 4）8。利用单晶X射线衍射数据确定了钙钛矿的晶体结构。空间群为P 2 1 / ç，一个= 12.6346（8），b = 9.0760（6），C ^ = 12.7560（8）埃，β= 108.75（9）°，V = 1385.1（3）3，Z＝ 2且R 1＝ 0.051。有一个Cu和六个Na位，其中之一也被必需的Ca占据。Cu原子形成五个范围为1.980-2.180Å的Cu-O键和两个≈2.9Å的长键，从而形成CuO 7多面体，该多面体与SO 4四面体共享角，从而形成孤立的[Cu 2（SO 4）8 ] 12个群集。这些簇被Na位点包围，这些位点将它们链接成一个三维框架。莫氏硬度为4。矿物为双轴（+），α= 1.498（3），βcalc= 1.500，γ= 1.516（3）和2V = 20（10）（λ= 589 nm）。粉末X射线衍射图的7条最强线为[ d，Å（I，％）（hkl）]：7.21（27）（110）；6.25（38）（102）; 4.47（31）（212）; 3.95（21）（30 $ \ bar {2} $ ）; 3.85（17）（121）; 3.70（36）（202）; 和3.65（34）（22 $ \ bar {1} $ ）。该矿物以Tomas Georgievich Petrov博士（生于1931年）的名字命名，以表彰他对矿物学和晶体学的贡献，尤其是对珠宝首饰孔雀石工业制造技术的发展。