Price per carat:$.50 - $50 Fluorite is found in shades of purple, blue and green. The stone can be highly polished and cut into a multifaceted gem with the brilliance of a more expensive gem.

From Jennifer Lopez's pink engagement ring to Kim Kardashian's 15-carat stunner, read on for a roundup of some of the most expensive celebrity rings of all time.

Some of these stones are found in just one or two places on Earth, while others are so scarce that fewer than a handful exist worldwide. The red diamond tops the list as the most expensive Diamond ...

So, what makes black opal so hard to find? And why is it so expensive? Black opal is one of the most enchanting stones in the world, sought after for its seemingly infinite display of colors.