Abstract Oxycalciomicrolite (IMA2019-110), (Ca,Na)2(Ta,Nb,Ti)2O6(O,F), is a new member of microlite-group mineral found in the saprolite of the weathered Fumal pegmatite, located close to the city of Nazareno, Minas Gerais state, Brazil. It occurs as an accessory mineral associated with quartz, albite, microcline, muscovite, columbite-subgroup minerals, cassiterite, hematite, ilmenite, monazite-(Ce), xenotime-(Y), zircon, beryl, spinel, epidote and garnet-group minerals. Oxycalciomicrolite is found as octahedral crystals, occasionally modified to rhombododecahedra, ranging from 0.2 to 0.5 mm in size. The crystals are brownish-yellow to brownish-red and translucent, with white streak and vitreous to resinous lustre. The tenacity is brittle, with a Mohs hardness of 5–5½. Cleavage and parting are not observed; the fracture is conchoidal. Electron microprobe analysis, Raman and infrared spectroscopies and X-ray powder diffraction were applied to characterise this mineral. Oxycalciomicrolite is isotropic, ncalc. = 2.037, and the calculated density is 6.333 g/cm3. The composition is (Ca1.57□0.26Na0.06Sn0.03Sr0.03U0.02Mn0.02Fe0.01Ce0.01)∑2.00(Ta1.79Nb0.18Ti0.03)∑2.00O6.00[O0.64F0.19□0.17]∑1.00 analysed by electron microprobe using wavelength dispersive spectrometry. The unit-cell parameters obtained by Pawley fitting from powder X-ray diffraction data are a = 10.4325(4) Å and V = 1135.46(14) Å3 with Z = 8.

中文翻译：

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Oxycalciomicrolite, (Ca,Na)2(Ta,Nb,Ti)2O6(O,F)，来自巴西米纳斯吉拉斯州古元古代圣若昂德尔雷伟晶岩省的微晶石群（烧绿石超群）的新成员

摘要 Oxycalciomicrolite (IMA2019-110), (Ca,Na)2(Ta,Nb,Ti)2O6(O,F)，是在风化的 Fumal 伟晶岩腐泥土中发现的微晶石族矿物的新成员，位于巴西米纳斯吉拉斯州纳萨雷诺市。它作为与石英、钠长石、微斜长石、白云母、铌铁矿亚群矿物、锡石、赤铁矿、钛铁矿、独居石-(Ce)、磷钇矿-(Y)、锆石、绿柱石、尖晶石、绿帘石和石榴石群相关的副矿物出现矿物质。Oxycalciomicrolite 被发现为八面体晶体，偶尔被修改为菱十二面体，尺寸从 0.2 到 0.5 毫米不等。晶体呈棕黄色至棕红色，半透明，有白色条纹和玻璃状至树脂光泽。韧性较脆，莫氏硬度为 5-5½。未观察到解理和分离；断口呈贝壳状。电子探针分析、拉曼光谱和红外光谱以及 X 射线粉末衍射被用于表征这种矿物。Oxycalciomicrolite 是各向同性的，ncalc。= 2.037，计算出的密度为 6.333 g/cm3。成分为(Ca1.57□0.26Na0.06Sn0.03Sr0.03U0.02Mn0.02Fe0.01Ce0.01)∑2.00(Ta1.79Nb0.18Ti0.03)∑2.00O6.00[O0.64F0.7]□□ ∑1.00 通过电子微探针使用波长色散光谱法进行分析。通过 Pawley 拟合从粉末 X 射线衍射数据获得的晶胞参数为 a = 10.4325(4) Å 和 V = 1135.46(14) Å3，Z = 8。01Ce0.01)∑2.00(Ta1.79Nb0.18Ti0.03)∑2.00O6.00[O0.64F0.19□0.17]∑1.00 通过电子微探针使用波长色散光谱法进行分析。通过 Pawley 拟合从粉末 X 射线衍射数据获得的晶胞参数为 a = 10.4325(4) Å 和 V = 1135.46(14) Å3，Z = 8。01Ce0.01)∑2.00(Ta1.79Nb0.18Ti0.03)∑2.00O6.00[O0.64F0.19□0.17]∑1.00 通过电子微探针使用波长色散光谱法进行分析。通过 Pawley 拟合从粉末 X 射线衍射数据获得的晶胞参数为 a = 10.4325(4) Å 和 V = 1135.46(14) Å3，Z = 8。