Natromelansonite, Na3Zr[Si7AlO19]⋅4–5H2O, was found at the Poudrette (Demix) quarry, Mont Saint-Hilaire, Quebec, Canada in a highly altered pegmatite together with a clay mineral, steacyite, polylithionite and rhodochrosite. It occurs as an outer zone of tabular crystals to 0.1 × 0.3 × 1 mm in size flattened on (001). The inner zone is made of melansonite. The mineral is grey with white powder colour and vitreous lustre. The cleavage is parallel to {010}, perfect. The Mohs hardness is 3.5. The mineral has green fluorescence under short-wave ultraviolet light. The Dcalc is 2.31 g/cm3. The infrared spectrum is reported. The composition (wt.%, average of 8 analyses) is Na2O 10.08, K2O 1.72, CaO 0.24, BaO 0.32, MnO 0.10, Al2O3 6.86, Y2O3 0.35, Yb2O3 0.55, SiO2 56.23, ZrO2 14.78, H2O 9.52, total 100.75. The empirical formula calculated on the basis of O = 23 apfu and H = 8 apfu is Na(□Na0.38Ca0.02Mn0.01)2(Na0.70K0.28Ba0.02)Σ1.00(Zr0.91Y0.02Yb0.02)Σ0.95(Si7.08Al1.02)Σ8.10O19⋅4H2O. The mineral is monoclinic, P21/m, a = 6.5156(3) Å, b = 24.061(1) Å, c = 6.9759(6) Å, β = 90.453(5)° and V = 1093.61(9) Å3 and Z = 2. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 12.02(100)(020), 6.97(89)(001), 6.51(39)(100), 3.416(37)(160), 3.062(42)($\bar{1}$61, 102, 161 and $\bar{1}$12), 3.018(38)(230 and 042), 2.864(40)(240 and 132). The crystal structure, solved and refined from single-crystal X-ray diffraction data (R1 = 0.042), is based on a double sheet of tetrahedra (T) and a sheet of octahedra (O) that alternate along the [010] direction forming a TOT structure typical for members of the rhodesite mero-plesiotype series.

Natromelansonite，Na 3 Zr[Si 7 AlO 19 ]⋅4–5H 2 O，在加拿大魁北克省 Mont Saint-Hilaire 的 Poudrette（Demix）采石场发现于高度蚀变伟晶岩中，以及粘土矿物、硬石、聚锂矿中和菱锰矿。它作为板状晶体的外部区域出现，尺寸为 0.1 × 0.3 × 1 mm，扁平于 (001)。内部区域由黑钠石制成。矿物呈灰色，带白色粉末，有玻璃光泽。解理与{010}平行，完美。莫氏硬度为3.5。该矿物在短波紫外光照射下呈绿色荧光。 D计算值为2.31g/cm 3。报告了红外光谱。组成（重量％，8次分析的平均值）为Na 2 O 10.08、K 2 O 1.72、CaO 0.24、BaO 0.32、MnO 0.10、Al 2 O 3 6.86、Y 2 O 3 0.35、Yb 2 O 3 0.55， SiO 2 56.23、ZrO 2 14.78、H 2 O 9.52，总计100.75。根据O=23 apfu、H=8 apfu计算的经验公式为Na(□Na 0.38 Ca 0.02 Mn 0.01 ) 2 (Na 0.70 K 0.28 Ba 0.02 ) Σ1.00 (Zr 0.91 Y 0.02 Yb 0.02 ) Σ0。 95 (Si 7.08 Al 1.02 ) Σ8.10 O 19 ⋅4H 2 O。矿物为单斜晶系，P 2 1 /m , a = 6.5156(3) Å, b = 24.061(1) Å, c = 6.9759(6) Å, β = 90.453(5)° 且V = 1093.61(9) Å 3且Z = 2。粉末 X 射线衍射图 [ d ,Å( I )( hkl )] 的最强反射为： 12.02(100 )(020)、6.97(89)(001)、6.51(39)(100)、3.416(37)(160)、3.062(42)( $\bar{1}$ 61、102、161 和$\bar {1} 12 美元)、3.018(38)（230 和 042）、2.864(40)（240 和 132）。根据单晶 X 射线衍射数据 ( R 1 = 0.042) 求解和精炼的晶体结构基于沿着 [010] 方向交替的双层四面体 (T) 和一层八面体 (O)形成罗得矿亚近型系列成员典型的 TOT 结构。