Some things to look for when shopping:
Cut: A diamond cut to proper proportions allows the greatest amount of light to be reflected resulting in maximum brilliance.
Clarity: Fewer inclusions in a diamond increases its value. A flawless diamond is extremely rare and valuable.
Color: Diamonds are found with a range of colors, from light yellow or brown to colorless, the rarest of the color spectrum.
Carat: A carat is a measurement of weight, which also includes size.
One carat = 200 Milligrams
Good luck and happy shopping!