Rewitzerite, K(H2O)Mn2(Al2Ti)(PO4)4[O(OH)](H2O)10⋅4H2O, is a new monoclinic member of the paulkerrite group, from the Hagendorf-Süd pegmatite, Oberpfalz, Bavaria, Germany. It was found in specimens of altered zwieselite, in association with rockbridgeite. Rewitzerite forms clusters of colourless elongated hexagonal-shaped prisms, up to 0.1 mm long. The crystals are flattened on {010} and elongated along [100], with forms {010}, {001}, {111} and {$\bar{1}$11}. The calculated density is 2.33 g⋅cm–3. Optically, rewitzerite crystals are biaxial (+), with α = 1.585(2), β = 1.586(2), γ = 1.615(2) (measured in white light) and 2V(meas) = 25(2)°. The empirical formula from electron microprobe analyses and structure refinement is A1[K0.77(H2O)0.23]A2[H2O] M1(Mn2+0.82Mg0.64Fe3+0.43□0.11)Σ2.00 M2+M3(Al1.51Ti4+1.06Fe3+0.43)Σ3.00(PO4)4 X[(OH)0.54F0.42O1.04]Σ2.00(H2O)10⋅4H2O, where □ = vacancy.

Rewitzerite has monoclinic symmetry with space group P21/c and unit-cell parameters a = 10.444(2) Å, b = 20.445(2) Å, c = 12.2690(10)Å, β = 90.17(3)°, V = 2619.8(6) Å3 and Z = 4. The crystal structure was refined using synchrotron single-crystal data to wRobs = 0.068 for 5894 reflections with I > 3σ(I). The crystal structure has the same topology as that for orthorhombic paulkerrite-group minerals but differs primarily in having an ordering of K+ and H2O molecules in different A sites, whereas they are disordered at a single A site in the orthorhombic members of the group.

钙镁石，K(H 2 O)Mn 2 (Al 2 Ti)(PO 4 ) 4 [O(OH)](H 2 O) 10 ⋅4H 2 O，是来自 Hagendorf 的泡铝石族的新单斜晶系成员-南伟晶岩，德国巴伐利亚上普法尔茨。它是在蚀变锆石标本中发现的，与岩桥石有关。钙镁石形成无色细长六角形棱柱簇，长度可达 0.1 毫米。晶体在{010}上变平并沿[100]拉长，形状为{010}、{001}、{111}和{ $\bar{1}$ 11}。计算出的密度为 2.33 g⋅cm –3。从光学角度看，利镁石晶体是双轴 (+) 的，α = 1.585(2)、β = 1.586(2)、γ = 1.615(2)（在白光下测量）和 2V(meas) =​​ 25(2)°。电子探针分析和结构精修的经验公式为A 1 [K 0.77 (H 2 O) 0.23 ] A2 [H 2 O] M 1 (Mn 2+ 0.82 Mg 0.64 Fe 3+ 0.43 □ 0.11 ) Σ2.00 M 2 + M 3 (Al 1.51 Ti 4+ 1.06 Fe 3+ 0.43 ) Σ3.00 (PO 4 ) 4 X [(OH) 0.54 F 0.42 O 1.04 ] Σ2.00 (H 2 O) 10 ⋅4H 2 O，其中 □ = 空缺。

菱镁矿具有单斜对称性，空间群为P 2 1 / c，晶胞参数a = 10.444(2) Å, b = 20.445(2) Å, c = 12.2690(10)Å, β = 90.17(3)°, V = 2619.8(6) Å 3和Z = 4。使用同步加速器单晶数据将晶体结构细化为wR obs = 0.068，对于 5894 次反射，I > 3σ( I )。该晶体结构与斜方镁铝沸石族矿物具有相同的拓扑结构，但主要不同之处在于不同A位点中 K +和 H 2 O 分子的有序性，而在斜方晶系成员中，它们在单个A位点上是无序的。团体。