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Why was molybdenum confused with graphite and lead ore for centuries?

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For at least 2,000 years, the mineral molybdenite was frequently confused with graphite and the lead ore galena due to their similar physical appearances.12

Specifically, molybdenite and graphite share a soft, greasy texture and a dark, metallic-looking luster, which led early observers to group them together based on these superficial characteristics. Because these minerals were often mistaken for lead, the name "molybdenum" was eventually derived from the Greek word molybdos, meaning "lead".32

This confusion persisted until 1778, when the Swedish chemist Carl Wilhelm Scheele demonstrated that the mineral molybdaina (molybdenite) was distinct from graphite and lead ore. He proved that it contained sulfur and a previously unidentified metal, which was subsequently isolated by Peter Jacob Hjelm in 1781.31