Other resources

• Industrial vs gem quality diamonds
  Diamonds are the hardest known naturally occurring material Its hardness has been known since ancient times, and is the source of its name. However, there have been synthetic diamonds created which are even harder.
  Read more: Industrial diamonds
• The National Gem Collection in the Smithsonian Collection
  Some of the world's most spectacular diamonds and other gems are located in the National Gem Collection in the Museum of Natural History in Smithsonian Collection in Washington, D.C. In the collection are diamonds known to almost everyone, such as the Hope Diamond, as well as other large diamonds and other precious gems and jewelry.
  Read more: National Gem Collection