Chromium is a steely-grey, lustrous, hard metal that takes a high polish and resists tarnishing.
Core Principles & Analysis
Louis-Nicolas Vauquelin discovered chromium in 1797 in the Siberian mineral crocoite and named it from the Greek for 'color'.
It is the hardest pure metal, and trace chromium impurities produce both the red of rubies and the green of emeralds.
At least 10.5% chromium turns iron into stainless steel by forming a self-repairing oxide film, and electroplated chromium gives tools and trim their hard, mirror finish.