The wonderful world of microscopic inclusions in gemstone:
http://www.smithsonianmag.com/science-nature/gems-minerals-inclusions-inside-photography-art-science-180953662/?no-ist
The wonderful world of microscopic inclusions in gemstone:
http://www.smithsonianmag.com/science-nature/gems-minerals-inclusions-inside-photography-art-science-180953662/?no-ist