Birthstones & AnniversariesOn almost all modern birthstone lists, diamond is recognized today as the birthstone for April. Diamond is also the gem that marks the 60th and 75th wedding anniversaries.
Diamonds are the hardest material on earth: 58 times harder than anything else in nature.
“Lucy” in the Sky
Fifty light years from earth, this star is a 10 billion-trillion-trillion carat diamond.
1 in 1,000,000
The average yield in most diamond mines is 1 part diamond to 1 million parts host rock.
- Mohs Hardness: 10
Where It's Found
There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.Learn More
Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.Learn More
Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.Learn More
Why We Love This Gemstone
The 4Cs, created by GIA, are considered the global language of diamond quality.
Diamond is the only gem composed of one single element: carbon.
A billion years
Most diamonds formed more than a billion years ago, deep in the earth’s mantle.
The human contribution to a diamond’s beauty is a well-executed cut.
Clarity grades assess the number, size, relief, and position of inclusions and blemishes.
The less color, the higher the grade. Even the slightest hint can make a dramatic difference in value.
Cut (proportions, symmetry, and polish) is a measure of how a diamond’s facets interact with light.
Rarity means larger diamonds of the same quality are worth more per carat.
Diamond Quality Factors: The Comprehensive Guide
Explore research on diamond history and diamond grading.
The Cullinan Diamond Centennial: A History and Gemological Analysis Of Cullinans I And IIKenneth Scarratt and Russell Shor , Jun 1, 2006 Read Article
GIA’S Symmetry Grading Boundaries for Round Brilliant Cut DiamondsRon H.Geurts, Ilene M. Reinitz, Troy Blodgett, and Al M. Gilbertson , Dec 1, 2011 Read Article
Color Grading “D-to-Z” Diamonds at the GIA LaboratoryJohn M. King, Ron H. Geurts, Al M. Gilbertson, and James E. Shigley , Dec 1, 2008 Read Article
The Nature of Diamonds
George E. Harlow