Sapphire quality factors
This ruby from Kashmir has an intense velvety blue color. Photo: Robert Weldon / Armed Islamic Group.
Sapphire is one of the big three colored gemstones for jewelry - the other two are sapphire and emerald. A durable stone designated as the September birthstone, it attracts jewelry buyers with its practicality and aura of romance.
Corundum is the mineral species that includes both ruby and sapphire as varieties. Red sapphire is known as sapphire and all other colored sapphires (including colorless or white sapphire as it is known in the trade) is sapphire, although blue is the most well-known.
Sapphire is generally known as a blue gemstone but surprisingly, it comes in a wide variety of colors and quality variations. In general, the more intense and harmonious the color is, the more valuable the stone is.
A non-blue sapphire is known as a luxury sapphire, and it may be in any color - except for red (which is a sapphire). Luxurious sapphire colors are: pink, orange, yellow, green, purple and violet. There is really a different color of sapphire to suit anyone's tastes!
Color has the most influence on the value of sapphire, and preferred sapphire has strong to vivid color saturation. The most valuable sapphires are velvety blue to blue-violet, with medium to medium-dark undertones. Sapphire with these qualities dominates the highest price per carat. A less valuable sapphire may also be gray, very light, or very dark.
Madagascar is a relatively newcomer as a major source of sapphire, but its stones can have an intense blue hue that rivals the best traditional sources. Copyright: GIA & Tino Hammid
What is a padparadsha sapphire?
An extremely rare and collectible variety that is a mixture of pink and orange is known in trade as padparadsha. Typically, these gemstones have a high value - much higher than many other fine sapphires. Their color can be difficult to describe. Some people say that the colors of the sapphire padparadsha should be called salmon or sunset. But the word padparadsha itself is derived from Sanskrit and indicates the rich color of the lotus flower.
Those who deal in this gem usually agree that the padparadsha sapphire should range from a light orange to a medium pink to a pinkish-orange.
Pink and purple sapphires
Pink sapphires range from bright red (pink) to light purple with a weak to intense color saturation that falls outside the color range of sapphire or purple sapphire. Purple sapphire is always the predominant color. They range from a medium to dark reddish purple to a violet-violet color with weak to vivid color saturation. The main luxury sapphire color categories are padparadscha, pink, purple, orange, yellow, green, colorless and black. Each category has its own color range, color and market reasons.
Some pink sapphires have an intensely saturated color. - Photo: Lydia Dyer, jewel from John Dyer & Co.
Sapphire yellow to orange sapphire
Yellow is also available in various color saturations from yellow to orange and light to dark, while sapphire orange has deep golden, to mandarin, and deep orange hues.
Yellow sapphire may be affected by other colors within the same gemstone and can range from light yellow to dark greenish yellow to orange-yellow with weak to severe color saturation. The finest yellow sapphire is yellow to orange yellow with bio-saturation.
Orange sapphires range from yellowish-orange to reddish-orange. The finest sapphires are strong orange, from pure orange to orange-red with medium tone and vivid saturation.
These sapphires range from yellow to a deep orange-yellow called golden to highly saturated reddish-orange. Copyright: GIA & Tino Hammid. Courtesy: Varujan Arslanian
A commercial grade sapphire may have an unwanted greenish blue or a strong greenish blue that can be seen during a gem display. A single, saturated green sapphire is actually rare and many collectors reward it. In sapphire green, a mixture of yellow and blue sapphires represents the color that a person sees.
Color-changing sapphire is a chameleon of corundum - stones that change color under different lighting. Under equivalent daylight (fluorescent or LED balanced daylight), the typical color-changing base sapphire ranges from blue to violet. Under the incandescent light, it ranges from a violet-violet to an intensely reddish violet. Some rare sapphires change color from green in daylight to reddish brown in incandescent light.
When gemologists judge a color-changing sapphire, they describe the color change as weak, moderate, or strong. The strength of a stone's discolouration is one of the most important quality factors affecting its value.
The color of the corundum has a huge impact on its value, although it is understood that small impurities are the cause of the asterisk. It can affect transparency and color, and only extremely rare exceptional gemstones exhibit transparency, color depth, and starry. As such, the best stellar corundum has a clear, distinct star against a highly saturated color. If the color is too light, it will not provide enough contrast to the rays of the star, and the star will be less visible.
Corundum can be red, pink, blue, black, gray, brown, purple,