Using a diamond anvil pressure cell and laser heating — to duplicate the mantle's unimaginable pressure and heat — they tested their recipe of bridgmanite with a pinch of ferric iron. (sciencedaily.com)
Studies by Professor Kappler's team in 2005 and 2010 showed that these bacteria transform dissolved ferric iron into iron oxide (rust)-- like the material in the early iron ores. (sciencedaily.com)
Small amounts of chromium impart the deep red color of ruby, traces of titanium and iron produce the stunning blue of sapphire, and chromium and ferric iron create the delicate orange shades of the extremely rare and costly padparadscha. (discovermagazine.com)