Short answers, pulled from the story.
Louis Nicolas Vauquelin isolated metallic chromium in 1797 by heating chromium trioxide in a charcoal oven. He had produced chromium trioxide three years earlier, in 1794, by mixing crocoite ore with hydrochloric acid. Vauquelin is credited as the true discoverer of the element.
The name chromium comes from the ancient Greek word chrōma, meaning color. The name was chosen because many chromium compounds are intensely colored, producing vivid yellows, oranges, reds, and greens.
Stainless steel and chrome plating together account for 85% of all commercial chromium use. Stainless steel forms when chromium is introduced to iron at concentrations above 11%, while chrome plating involves electrodepositing chromium onto metal surfaces.
The first laser, produced in 1960, used a synthetic ruby crystal as its active medium. That crystal was made by doping chromium(III) ions into artificial corundum, and the laser operated at a wavelength of 694.3 nanometers in the deep red part of the visible spectrum.
Hexavalent chromium is toxic and carcinogenic. When it enters the bloodstream it damages kidneys, liver, and blood cells through oxidation reactions, and ingestion has been linked to stomach tumors. Its carcinogenic risk to workers in chromate dye companies was first documented in a scientific publication in 1890.
South Africa is the largest producer, accounting for 48% of world chromium ore output in 2013, followed by Kazakhstan at 13%, Turkey at 11%, and India at 10%. Untapped reserves are concentrated in Kazakhstan and southern Africa.