Carat Weight
Carat weight refers to a diamonds weight on a very sensitive scale. A carat is broken into 100 points. The easiest way to remember this is that points are to carats what pennies are to dollars. Just like .50 cents is ½ dollar, 50 points is ½ carat. If you were looking at a .77 carat diamond it weighs 77 points, or just over 3/4 carat.
As a diamonds carat weight increase, so does its rarity and its price-per-carat. Amazingly, 250 TONS of dirt must be moved to find a single rough crystal that will produce a 1ct. finished diamond.
In this same amount of dirt there may be 5 crystals that will produce a ½ carat diamond and 20 crystals that will produce a .10 carat. This is why a 1 carat diamond may cost 4 times more than a comparable ½ carat diamond.