Explanatory notes
… in tungsten metallurgy, from wolframite (heading 26.11) and sodium carbonate; white leaflets or crystals, … Native calcium tungstate (scheelite), an ore ( heading 26.11 ). (b) Natural tungstates of manganese (hubnerite) or of iron (ferberite) ( heading 26.11 ). (c) Luminescent tungstates (e.g., of …