Discovery of chromium

Chromium was first discovered in a mineral called crocoite. The German prospector Johann Gottlieb Lehmann (1719-1767) first wrote about this red-orange mineral in 1761, calling it red lead. When Lehmann dissolved the red lead chromate mineral from Yekaterinburg, Siberia he observed and reported the green color of its hydrochloric acid solution.

He analyzed samples and wrongly thought they were made from the heavy metals lead and selenium.

The brought red-orange mineral was subsequently analyzed by various chemists, with different results and thus remained a matter of much curiosity and speculation for nearly three decades.

Nicolas-Louis Vauquelin 

Lehmann was not the first to observe the green color of chromium. As early as 2000 BC, emeralds were extracted from mines by the Red Sea, later called Cleopatra’s mines, Emerald is an aluminium beryllium silicate, a beryl. It has its beautiful green color just from chromium.

It was not until the French chemist Nicolas-Louis Vauquelin received some crystals of crocoites in 1797 that scientists realized the importance of the mineral.

In 1798 he obtained the pure metal. Vauquelin succeeded in isolating the chromium metal by heating a mixture of the chromic acid and carbon in a graphite crucible.  He also found traces of chromium in ruby and emerald gemstones.

The discovery that chromium affected glucose metabolism was reported by K. Schwarz and W. Mertz in 1959. Believed to contain chromium in an organic complex named the glucose tolerance factor or GTF, to date it has never been isolated or defined chemically from natural sources.
Discovery of chromium