Diamonds may be a girl's best friend, but those friends might be easier to find than formerly believed. Researchers from Johns Hopkins University have developed a model they believe means that in the deep, deep Earth, diamonds might not be rare at all. This is based on a theory that diamonds can be formed not just by the "redox" reactions commonly believed to have produced the diamonds we know today but also by water passing through rocks. Luckily for the diamond market, it's not going to make jewelry cheaper. At least not yet.