【摘要】 1980年在河北曲阳县某碱性伟晶岩中发现一种含Y、Ce、Ca、Al为主的硼硅酸盐矿物。经光性及其它物性的测定、化学分析、X射线单晶及粉晶分析、红外光谱分析确定是在我国首次发现的硼硅钇钙石（hellandite）、空间群为P2/a,晶胞参数a=18.827×10^-10m;b=4.694;c=10.257;β=111.7°;单位晶胞分子式:（Ca,Y,RE）₁₂(Al,Fe³⁺)₂（OH）₄[Si₈（B,Be）₈O₄₀（OH）₄]。更多还原

【Abstract】 Hellandite is a rare mineral which has been not reported in the Chinese literature. It was found in an alkaline pegmatite in 1980 from Quyang, Hebei Province, Chana. It associates with albite, quartz, magnetite, zircon, apatite, fergusonite, pyrochlore and gadolinite, etc.The mineral occurs as irregular grains (0.1-0.3^mm), as well as columnar and wedge forms, It is colorless or white, with vitreous lustre, H. VHN_100g=572kg/mm （5.81）, and SG, 3.83 （calculated）, 3.69-3.71 （measured）. It is optically biaxial positive and its indeices of refraction are Ng=1.730-1.733; Nm=1.723-1.727; Np=1.719-1.724; Ng-Np=0.009-0.011.The Chemical analysis gives （%）; Y₂O₃ 21.75; RE₂O₃, 16.78; CaO, 11.47; Na₂O, 0.08; K₂O, 0.36; Fe₂O₃, 2.83; MnO, 0.34; BeO, 1.40; FeO, 0.61; Al₂O₃, 4.06; B₂O₃, 11.07; SiO₂, 25.14; H₂O⁺, 3.81, and sum 99.70. The cell formula is:（Ca, Y, RE）₁₂(Al, Fe³⁺)₂（OH）₄[Si_s（B, Be）₈O₄₀（OH）₄]Space group of hellandite is P2/a, with monoclinic unit cell a=18.827×10^-10m, b=4.694, c=10.257, β=111.7, and V=842.21×10^-10m³. The strongest lines of the X-ray powder pattern are 4.679（36）, 3.434（90）, 2.883（88）, 2.812（94）, 2.634（100）, 2.608（68）, 2.167（28）, and 1.888（29）.更多还原