Nioboheftetjernite, ScNbO4, a new mineral from the Befanamo Pegmatite, Madagascar

IF 1.1 4区地球科学 Q3 MINERALOGY

Canadian Mineralogist Pub Date : 2021-03-30 DOI:10.3749/CANMIN.2000070

I. Lykova, R. Rowe, G. Poirier, A. McDonald, G. Giester

{"title":"Nioboheftetjernite, ScNbO4, a new mineral from the Befanamo Pegmatite, Madagascar","authors":"I. Lykova, R. Rowe, G. Poirier, A. McDonald, G. Giester","doi":"10.3749/CANMIN.2000070","DOIUrl":null,"url":null,"abstract":"\n A new mineral, nioboheftetjernite, ideally ScNbO4, was found in the Befanamo pegmatite, Analamanga, Madagascar. It occurs as anhedral grains and very crude elongated crystals up to 200 μm in length in an intergrowth with rossovskyite, ilmenite, rutile, thortveitite, euxenite-(Y), feldspar, and quartz. The mineral is black with dark-brown to black streak and submetallic luster. It has no cleavage and its fracture is uneven. Dcalc is 5.855 g/cm3. The Raman spectrum and reflectance data are reported. The chemical composition (wt.%) is MgO 0.06, MnO 2.49, Fe2O3 12.14, Sc2O3 11.34, TiO2 5.94, SnO2 1.45, Nb2O5 32.23, Ta2O5 29.93, WO3 3.38, total 98.96. The empirical formula calculated on the basis of 4 O apfu is (Sc0.40Fe3+0.37Ti0.15Mn2+0.08)Σ1.00(Nb0.58Ta0.33W0.03Ti0.03Sn0.02)Σ0.99O4. The simplified general formula is (Sc,Fe3+)(Nb,Ta)O4. Nioboheftetjernite is monoclinic, P2/c, a = 4.7092(3), b = 5.6531(4), c = 5.0530(4) Å, β = 90.453(3)°, and V = 134.515(17) Å3. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 4.722(22)(100), 3.776(22)(011), 3.628(44)(110), , 2.938(83)(111), 2.472(30)(021), and . The crystal structure, refined from single-crystal X-ray diffraction data (R1 = 0.016), is of the “wolframite” type. The mineral is named as the Nb-analogue of heftetjernite, ScTaO4.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":" ","pages":""},"PeriodicalIF":1.1000,"publicationDate":"2021-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Canadian Mineralogist","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.3749/CANMIN.2000070","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MINERALOGY","Score":null,"Total":0}

引用次数: 2

Abstract

A new mineral, nioboheftetjernite, ideally ScNbO4, was found in the Befanamo pegmatite, Analamanga, Madagascar. It occurs as anhedral grains and very crude elongated crystals up to 200 μm in length in an intergrowth with rossovskyite, ilmenite, rutile, thortveitite, euxenite-(Y), feldspar, and quartz. The mineral is black with dark-brown to black streak and submetallic luster. It has no cleavage and its fracture is uneven. Dcalc is 5.855 g/cm3. The Raman spectrum and reflectance data are reported. The chemical composition (wt.%) is MgO 0.06, MnO 2.49, Fe2O3 12.14, Sc2O3 11.34, TiO2 5.94, SnO2 1.45, Nb2O5 32.23, Ta2O5 29.93, WO3 3.38, total 98.96. The empirical formula calculated on the basis of 4 O apfu is (Sc0.40Fe3+0.37Ti0.15Mn2+0.08)Σ1.00(Nb0.58Ta0.33W0.03Ti0.03Sn0.02)Σ0.99O4. The simplified general formula is (Sc,Fe3+)(Nb,Ta)O4. Nioboheftetjernite is monoclinic, P2/c, a = 4.7092(3), b = 5.6531(4), c = 5.0530(4) Å, β = 90.453(3)°, and V = 134.515(17) Å3. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 4.722(22)(100), 3.776(22)(011), 3.628(44)(110), , 2.938(83)(111), 2.472(30)(021), and . The crystal structure, refined from single-crystal X-ray diffraction data (R1 = 0.016), is of the “wolframite” type. The mineral is named as the Nb-analogue of heftetjernite, ScTaO4.

查看原文本刊更多论文

Nioboheftetjernite，ScNbO4，马达加斯加Befanamo伟晶岩中的一种新矿物

在马达加斯加Anaramanga的Befanamo伟晶岩中发现了一种新矿物，nioboheftetjernite，理想情况下为ScNbO4。它以二面体颗粒和非常粗糙的细长晶体的形式出现，长度可达200μm，与rossovskyite、钛铁矿、金红石、钍云母、辉石-（Y）、长石和石英共生。该矿物为黑色，具有深棕色至黑色条纹和亚金属光泽。无解理，断裂不均匀。Dcalc为5.855 g/cm3。报道了拉曼光谱和反射率数据。化学成分（wt.%）为MgO 0.06、MnO 2.49、Fe2O3 12.14、Sc2O3 11.34、TiO2 5.94、SnO2 1.45、Nb2O5 32.23、Ta2O5 29.93、WO3 3.38，总计98.96。根据4O apfu计算的经验公式为（Sc0.40Fe3+0.37Ti0.15Mn2+0.08）∑1.00（Nb0.58Ta0.33W0.03Ti0.03Sn0.02）∑0.99O4。简化的通式为（Sc，Fe3+）（Nb，Ta）O4。Nioboheftetjernite为单斜晶系，P2/c，a=4.7092（3），b=5.6531（4），c=5.0530（4）Å，β=90.453（3）°，V=134.515（17）Å3。粉末X射线衍射图[d，Å（I）（hkl）]的最强反射为：4.722（22）（100）、3.776（22））（011）、3.628（44）（110）、2.938（83）（111）、2.472（30）（021）和。从单晶X射线衍射数据（R1=0.016）中提炼出的晶体结构为“黑钨矿”型。该矿物被命名为重晶石的Nb类似物，ScTaO4。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Canadian Mineralogist 地学-矿物学

CiteScore

2.20

自引率

22.20%

发文量

审稿时长

4-8 weeks

期刊介绍： Since 1962, The Canadian Mineralogist has published papers dealing with all aspects of mineralogy, crystallography, petrology, economic geology, geochemistry, and applied mineralogy.