How Do I Tell the Quality of a Blue Sapphire?

Blue is the most popular and well-known color in sapphires. Quality in colored gemstones is judged in terms of factors such as color, clarity, weight, and cut, according to American Gemological Laboratories or AGL.

Color

Sapphire blues can range from light pastel to midnight blue. Strong medium-blue colors in sapphires are more valued, according to the Gemological Institute of America or GIA. Blue sapphires from Myanmar (Burma) and Kashmir are especially valued.

Clarity

Clarity refers to the transmission of light and lack of inclusions. Better sapphires have greater clarity. According to GIA, natural sapphires are commonly heated to dissolve titanium inclusions, thereby increasing clarity and bringing out more color.

Cut and Weight

Cut is used to describe the overall appearance of a gemstone. A colored gemstone like a sapphire is usually cut to conserve its weight rather than "according to strict mathematical parameters," according to AGL. Weights above one carat are more desirable. Round cuts, cushion, heart, pear, marquise and emerald cuts are all used for sapphires.

References

• Gemological Institute of America: How to Buy a Gemstone
• American Gemological Laboratories: AGL Prestige Report