A new mineral, dioskouriite, CaCu₄Cl₆(OH)₄∙4H₂O, represented by two polytypes, monoclinic (2M) and orthorhombic (2O), which occur together, was found in moderately hot zones of two active fumaroles, Glavnaya Tenoritovaya and Arsenatnaya, at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. Dioskouriite seems to be a product of the interactions involving high-temperature sublimate minerals, fumarolic gas and atmospheric water vapor at temperatures not higher than 150 °C. It is associated with avdoninite, belloite, chlorothionite, eriochalcite, sylvite, halite, carnallite, mitscherlichite, chrysothallite, sanguite, romanorlovite, feodosiyite, mellizinkalite, flinteite, kainite, gypsum, sellaite and earlier hematite, tenorite and chalcocyanite in Glavnaya Tenoritovaya and with avdoninite and earlier hematite, tenorite, fluorophlogopite, diopside, clinoenstatite, sanidine, halite, aphthitalite-group sulfates, anhydrite, pseudobrookite, powellite and baryte in Arsenatnaya. Dioskouriite forms tabular, lamellar or flattened prismatic, typically sword-like crystals up to 0.01 mm × 0.04 mm × 0.1 mm combined in groups or crusts up to 1 × 2 mm² in area. The mineral is transparent, bright green with vitreous luster. It is brittle; cleavage is distinct. The Mohs hardness is ca. 3. D_meas is 2.75(1) and D_calc is 2.765 for dioskouriite-2O and 2.820 g cm⁻³ for dioskouriite-2M. Dioskouriite-2O is optically biaxial (+), α = 1.695(4), β = 1.715(8), γ = 1.750(6) and 2V_meas. = 70(10)°. The Raman spectrum is reported. The chemical composition (wt%, electron microprobe data, H₂O calculated by total difference; dioskouriite-2O/dioskouriite-2M) is: K₂O 0.03/0.21; MgO 0.08/0.47; CaO 8.99/8.60; CuO 49.24/49.06; Cl 32.53/32.66; H₂O(calc.) 16.48/16.38; -O=Cl −7.35/−7.38; total 100/100. The empirical formulae based on 14 O + Cl apfu are: dioskouriite-2O: Ca_1.04(Cu_4.02Mg_0.01)_Σ4.03[Cl_5.96(OH)_3.90O_0.14]_Σ10∙4H₂O; dioskouriite-2M: (Ca_1.00K_0.03)_Σ4.03(Cu_4.01Mg_0.08)_Σ4.09[Cl_5.99(OH)_3.83O_0.18]_Σ10∙4H₂O. Dioskouriite-2M has the space group P2₁/c, a = 7.2792(8), b = 10.3000(7), c = 20.758(2) Å, β = 100.238(11)°, V = 1531.6(2) ų and Z = 4; dioskouriite-2O: P2₁2₁2₁, a = 7.3193(7), b = 10.3710(10), c = 20.560(3) Å, V = 1560.6(3) ų and Z = 4. The crystal structure (solved from single-crystal XRD data, R = 0.104 and 0.081 for dioskouriite-2M and -2O, respectively) is unique. The structures of both polytypes are based upon identical BAB layers parallel to (001) and composed from Cu²⁺-centered polyhedra. The core of each layer is formed by a sheet A of edge-sharing mixed-ligand octahedra centered by Cu(1), Cu(2), Cu(3), Cu(5) and Cu(6) atoms, whereas distorted Cu(4)(OH)₂Cl₃ tetragonal pyramids are attached to the A sheet on both sides, along with the Ca(OH)₂(H₂O)₄Cl₂ eight-cornered polyhedra, which provide the linkage of the two adjacent layers via long Ca−Cl bonds. The Cu(4) and Ca polyhedra form the B sheet. The difference between the 2M and 2O polytypes arises as a result of different stacking of layers along the c axis. The cation array of the layer corresponds to the capped kagomé lattice that is also observed in several other natural Cu hydroxychlorides: atacamite, clinoatacamite, bobkingite and avdoninite. The mineral is named after Dioskouri, the famous inseparable twin brothers of ancient Greek mythology, Castor and Polydeuces, the same in face but different in exercises and achievements; the name is given in allusion to the existence of two polytypes that are indistinguishable in appearance but different in symmetry, unit cell configuration and XRD pattern.

中文翻译：

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硅藻土，CaCu4Cl6（OH）4∙4H2O：一种新的矿物描述，晶体化学和多型性

一种新的矿物，脉钙铁矿，CaCu ₄ Cl ₆（OH）₄ ∙4H ₂ O，以单斜晶系（2 M）和斜方晶系（2 O）一起出现在俄罗斯堪察加半岛Tolbachik火山大Tolbachik裂谷爆发北部突破的第二个火山口锥体的两个活跃的喷气孔Glavnaya Tenoritovaya和Arsenatnaya的中等高温区。硅藻土似乎是高温下升华的矿物，富马酸气体和大气水蒸气在不高于150°C的温度下相互作用的产物。它与磷灰石，颠茄石，次氯酸铝石，锂碳铝石，钾盐，盐岩，钠盐岩，硅镁石，辉石，辉石，闪锌矿，锰铁矿，辉石硅藻土，硅铝石，氟锌铁矿，kainite，石膏，硅藻土，钙钛矿，堇青石，堇青石，蝶鞍石和硅镁石相关联以及更早的赤铁矿，球铁矿，氟金云母，透辉石，斜铁锂辉石，山铁矿，盐岩，Arsenatnaya中的磷灰石族硫酸盐，硬石膏，假板钛矿，弹性体和重晶石。硅藻土形成平板状，层状或扁平棱柱形，通常为剑状晶体，最大0.01 mm×0.04 mm×0.1 mm，成组组合或结壳，最大1×2 mm^2个区域。矿物是透明的，鲜绿色，具有玻璃光泽。它很脆；裂解是不同的。莫氏硬度为约。3. Dioskouriite-2 O的D _meas为2.75（1），D _calc为2.765 ，而dioskouriite-2 M的D _calc为2.820 g cm ^-3。Dioskouriite-2 O是光学双轴（+），α= 1.695（4），β= 1.715（8），γ= 1.750（6）和2 V_测量值。= 70（10）°。报告了拉曼光谱。化学组成（wt％，电子微探针数据，通过总差计算的H ₂ O； dioskouriite-2 O / dioskouriite-2 M）为：K ₂O 0.03 / 0.21；氧化镁0.08 / 0.47; CaO 8.99 / 8.60；CuO 49.24 / 49.06; Cl 32.53 / 32.66；H ₂ O（计算）16.48 / 16.38; -O = Cl −7.35 / −7.38; 总计100/100。基于14 O + Cl apfu的经验公式为：dioskouriite-2 O：Ca _1.04（Cu _4.02 Mg _0.01）_Σ4.03 [Cl _5.96（OH）_3.90 O _0.14 ] _Σ10 ∙4H ₂ O; dioskouriite-2 M：（Ca _1.00 K _0.03）_Σ4.03（Cu _4.01 Mg _0.08）_Σ4.09 [Cl _5.99（OH）_3.83 O _0.18 ] _Σ10 ∙4H ₂ O. Dioskouriite-2 M具有空间群P 2 ₁ / c，a = 7.2792（8），b = 10.3000（7），c = 20.758（2）Å，β= 100.238（ 11）°，V = 1531.6（2）埃³和ž = 4; dioskouriite-2 ö：P 2 ₁ 2 ₁ 2 ₁，一= 7.3193（7），b = 10.3710（10），C ^ = 20.560（3）埃，V = 1560.6（3）³和Z =4。晶体结构（根据单晶XRD数据解析，对于dioskouriite-2 M和-2 O分别为R = 0.104和0.081 ）。两种多型的结构均基于平行于（001）且由以Cu ^2+为中心的多面体组成的相同BAB层。每层的核心由一片以Cu（1），Cu（2），Cu（3），Cu（5）和Cu（6）原子为中心的边共享混合配体八面体的薄片A形成（4）（OH）₂氯_3级四方的金字塔被附接到甲两侧片，随着的Ca（OH）₂（H ₂O）₄ Cl ₂八角多面体，通过长的Ca-Cl键提供两个相邻层的连接。Cu（4）和Ca多面体形成B片。2 M和2 O多型之间的差异是由于沿c层的不同堆积而产生的轴。该层的阳离子阵列对应于封端的kagomé晶格，该晶格也可在其他几种天然铜羟基氯化物中观察到：滑石粉，斜铁石粉，水滑石和钠钙皂石。这种矿物以古希腊神话中著名的不可分割的孪生兄弟Dioskouri，Castor和Polydeuces的名字命名，它们的面容相同，但运动和成就却有所不同。该名称是指存在两个在外观上无法区分但在对称性，晶胞构型和XRD图谱上不同的多型体。