Diamond forms under high temperature and pressure conditions that exist only about 100 miles beneath the earth’s surface. Diamond’s carbon atoms are bonded in essentially the same way in all directions. Another mineral, graphite, also contains only carbon, but its formation process and crystal structure are very different. Graphite is so soft that you can write with it, while diamond is so hard that you can only scratch it with another diamond.
Birthstones & AnniversariesOn almost all modern birthstone lists, diamond is recognised 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.
Where It's Found
There are a number of processes used to alter the colour or apparent clarity, or to 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 man-made 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 colour, 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 Gemmological Analysis Of Cullinans I And IIKenneth Scarratt and Russell Shor , Jun 1, 2006 Read more in English
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 more in English
Colour Grading “D-to-Z” Diamonds at the GIA LaboratoryJohn M. King and Ron H. Geurts, Al M. Gilbertson, and James E. Shigley , Dec 1, 2008 Read more in English