| ⓘ 'Aeschynite' Description: Aeschynite occur in thin pockets in association with greisenised zones. In polished sections it is optically isotropic because of its metamict nature. At normal temperatures, aeschynite do not show its characteristic XRD pattern; however, on heating at about 900 - 1000 degrees aeschynite show its characteristic XRD pattern. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Albite Formula: Na(AlSi3O8) Description: The albitised pegmatites contain grey - white, and earthy albite. Due to pervasive albitisation, some of the perthites have been almost completely replaced by albite. Albite also occurs as the cleavelandite
variety and / or equigranular saccharoidal aggregates of sugary albite, with or without intergrown tiny quartz grains and greenish mica. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Albite var. Cleavelandite Formula: Na(AlSi3O8) References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Almandine Formula: Fe2+3Al2(SiO4)3 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Beryl Formula: Be3Al2(Si6O18) Description: Beryl is mostly earthy-white, greenish, occasionally yellowish, with or without iron oxide stainings, particularly along fractures. It occurs in various sizes ranging from tiny to large euhedral crystals. It exhibits a columnar habit, representing a combination of hexagonal prism and a pinacoid. Often, euhedral crystals measuring from 1 cm in length and less than 1 cm in width to 30 cm in length and 15 cm in width have been found around the quartz core. In places, well-developed prismatic crystals occur within the quartz core, which vary in size from 1 cm in length and less than 1 cm in diameter to 10 cm in length and 10 cm in diameter. Twinned and zoned crystals are also present. Significantly, abundant beryl crystals of different sizes have also been found studded within perthite zones. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ 'Biotite' Formula: K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Cassiterite Formula: SnO2 Description: Cassiterite occurs in albitised pegmatites in the form of small anhedral to euhedral crystals. In albitised portions, pockets of aggregates of euhedral cassiterite crystals have been found. In certain pegmatites pockets, cassiterite aggregates of up to 15 cm x 12 cm x 8 cm have been found. XRD analysis of cassiterite revealed that apart from cassiterite (bulk), trace amounts of ixiolite, wodginite, microlite, and ilmenite are also present in it as intergrown phases. Albite is the main host mineral of cassiterite. Minor silvery white mica, sugary albite, and cleavelandite are associated with cassiterite in the Sn-pegmatites. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Columbite-(Fe) Formula: Fe2+Nb2O6 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ 'Columbite-Tantalite' Habit: tabular Colour: black and brownish black Description: Columbite-tantalite is black and brownish black, and is fine to coarse-grained, massive, tabular (generally 0.1 -2.0 cm thick), and vertically stacked crystals. It occurs randomly distributed in the intermediate zone, but is mostly located close to quartz core. The largest crystal found was 15 cm in length, 11cm in breadth, and 4.5 cm in thickness. In addition, it also occurs as fine grains and lumps.
Intergrown columbite-tantalite and ixiolite crystals may occur with relative variable abundances. Such intergrowths contain more Ta than Nb. Columbite-tantalite shows large chemical variations. It contains 30.93 to 58.51% Nb2O5, 16.32 to 38.80% Ta2O5, and 0.84 to 16.77% SnO2. In general Fe (10.08 to 15.19% FeO) predominates over Mn (2.84 to 6.78% MnO), with Ta/(Ta+Nb) 0.25 to 0.64 and Mn/(Mn+Fe) 0.51 to 0.37.
Appreciable amounts of W (0.38 to 1.40% WO3) and Ti (1.43 to 2.64% TiO2) are also present.
The columbite-tantalite is invariably radioactive due to presence of U (0.08 to 0.17% U3O8) and Th (0.02 to 1.03% ThO2) contents References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Euxenite-(Y) Formula: (Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6 Description: Euxenite occur in thin pockets in association with greisenised zones. Polished sections are optically isotropic because of their metamict nature. At normal temperatures, euxenite do not show its characteristic XRD patterns; however, on heating at about 800 euxenite show its characteristic XRD patterns. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
ⓘ 'Feldspar Group'References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
ⓘ 'Feldspar Group var. Perthite'References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Fersmite Formula: CaNb2O6 Description: Fersmite occurs as a minor phase associated with columbite-tantalite. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Hematite Formula: Fe2O3 |
| ⓘ Ilmenite Formula: Fe2+TiO3 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ 'Ixiolite-(Mn2+)-Ixiolite-(Fe2+) Series' Description: Ixiolite is iron black to greyish in colour with (determined) specific gravity varying between 5.34 and 6.65. In a pegmatite at Metapal, it is the main ore mineral that occurs in all the zones as a major Nb-Ta mineral.
Fe rich, Nb-dominant ixiolite has been analysed. It is characterized by a high Nb (58.8% Nb2O5)and low Ta (14.2% Ta2O5)content. The Sn content is also very low (0.3% SnO2). It is also Fe dominant as the FeO (10.6%) content is two times more than MnO (5.6%) content. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Magnetite Formula: Fe2+Fe3+2O4 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Microcline Formula: K(AlSi3O8) Description: Perthitic and non-perthitic microcline is the main feldspar. Coarse crystals and blebs of perthite are also seen within the quartz cores near their margins. Coarse-grained feldspar lenses are cut by irregular masses of grey quartz, which themselves contain subhedral perthitic crystals. The inner parts of the intermediate zones of several zoned pegmatites consist almost entirely of perthite, whereas,
the outer parts comprise intergrowths of quartz, feldspar, and muscovite and occasionally biotite. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ 'Microlite Group' Formula: A2-mTa2X6-wZ-n Description: Microlite occurs in association with columbite-tantalite and also independently. However, it is difficult to distinguish it megascopically from other Nb-Ta phases References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Monazite-(Ce) Formula: Ce(PO4) Description: Brownish yellow monazite occurs as fine- to coarse grained fragments, lumps, and crystals. The monazite has also been observed in jig concentrates of many pegmatites, having a concentration of less than 1% with crystals of up to 1.3 cm in size. It also occurs in anhedral, tabular, and elongated habits. Bigger crystals display flattened [100] or elongated [100] habit, and show development of (100) or (111) faces. Crystal faces are smooth, pitted, or striated. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Muscovite Formula: KAl2(AlSi3O10)(OH)2 Description: Primary muscovite is colourless or ruby red, and present almost in all pegmatite zones. Bigger books and tabular crystals up to 15 cm across are present in wall / intermediate zones of the pegmatites. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ 'Plagioclase' Formula: (Na,Ca)[(Si,Al)AlSi2]O8 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Quartz Formula: SiO2 Description: Massive or fractured, colourless to milky white and opalescent quartz is the most abundant mineral that is present in all zones of the pegmatites. In the core, it is present as a massive body or small disconnected lenses. At places, it is brecciated and crushed into pieces of variable lengths (3-8 cm) being set in a siliceous and ferruginous groundmass. Quartz crystals with comb pattern are also found. Occasionally, quartz occurs in miarolitic cavities of various shapes and sizes. References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ 'Tapiolite' Formula: (Fe,Mn)(Ta,Nb)2O6 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Topaz Formula: Al2(SiO4)(F,OH)2 References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Wodginite Formula: Mn2+Sn4+Ta2O8 |
ⓘ 'Xenotime'References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |
| ⓘ Zircon Formula: Zr(SiO4) References: Singh, Yamuna, Pandit, P. S. C., Bagora, Sanjay, Jain, P. K. (2017) Mineralogy, geochemistry, and genesis of co-genetic granite-pegmatite-hosted rare metal and rare earth deposits of the Kawadgaon area, Bastar craton, Central India. Journal of the Geological Society of India, 89 (2) 115-130 doi:10.1007/s12594-017-0574-2 |