|Natural ruby crystals from Winza, Tanzania|
Photo Source: Wikipedia
It seems ruby formation is a miracle of sorts. Geologists, gemologists, and chemists know what they’re comprised of, and their primary geological locations lend themselves to some educated speculation as to how they form, but their unique properties present a mystery that is, as yet, unsolved.
The mystery revolves around the absence of silica and the low amount of iron in their structure. Considering that silica and iron are two of the most copious minerals on Earth, it baffles geologists as to which process would eliminate silica and minimize iron enough for rubies to form. In addition to the absence of these elements, chromium (one of the rarest elements on earth) must find its way into the aluminum crystal grid to lend rubies their brilliant red hues. This is also confounding to geologists.
So, just how does a gemstone, which requires no silica, low amounts of iron, and the presence of a rare element, chromium, form? One theory is the Tethys Sea Theory
1. Sasso, Anne. "The Geology of...Rubies." Discover Magazine, November 2004. Accessed May 21, 2012. http://discovermagazine.com/2004/nov/geology-of-rubies.
2. "How are Rubies Formed." Want To Know It. Accessed May 21, 2012. http://wanttoknowit.com/how-are-rubies-formed/.
*Clip art courtesy of The Graphics Fairy