Where sapphire gets its blue tint mainly from iron, rubies get their pink to blood-red hue from chromium. So [NightHawkInLight]’s recipe starts with aluminum oxide grit-blasting powder and ...

In Sweden, around 18,000 workers are exposed to hexavalent chromium in their workplace. Hexavalent chromium is a powerful carcinogen that is released, for example, during welding of stainless steel or ...