submetallic
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submetallic |
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| navigate by keyword : africa background baltic black coltan columbite conflict congolese crystal estonia gem gemstone geological geologist geology hand igneous jewel jewelry kalemie kongo macro mine mineral modern most niobium ore piece porphyritic porphyry precious proterozoic quartz red rhyolite rock sea skin stone tantalite tantalum technology underground used volcanic white widely wound |
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| Columbite, also called niobite, niobite-tantalite and columbate [Fe, MnNb2O6], is a black mineral group that is an ore of niobium. It has a submetallic luster and a high density and is a niobate of iron and manganese. This mineral group was first found in Haddam, Connecticut, in the United States. It forms a series with the tantalum-dominant analogue ferrotantalite and one with the manganese-dominant analogue manganocolumbite. The iron-rich member of the columbite group is ferrocolumbite. Some tin and tungsten may be present in the mineral. Yttrocolumbite is the yttrium-rich columbite with the formula Y,U,FeNb,TaO4. It is a radioactive mineral found in Mozambique. |
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Stockphotos.ro (c) 2025. All stock photos are provided by Dreamstime and are copyrighted by their respective owners. |
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