Ibikoresho bito hamwe nibigize imiti Icupa ryibirahure muri rusange bigizwe nubwoko 7-12 bwibikoresho fatizo.Hano hari umucanga wa quartz, ivu rya soda, hekeste, dolomite, feldspar, borax, gurş na barium.Mubyongeyeho, hari ibikoresho byingirakamaro nkibisobanuro, amabara, decolora ...
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