Both contain iron, manganese, columbium and tantalum. They are so hard that they cannot be scratched with a knife, unless it contains unusually hard steel. A piece of quartz will scratch them. They are much heavier than most minerals, the actual specific gravity of each being 7, nearly two and one-half times as heavy as quartz. The pure mineral contains 70 per cent metal, but the percentage in actual minerals is lower.
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Get Paid to search. Earn cash referring friends. Win cool prizes. It's a rare metal, but one with everyday uses. Tantalum is found in the guts of cellular phones, computers, pagers and even Sony's Playstation 2 and Nintendo's Gameboy.