Sapphires: Value, Quality and How They Are Evaluated

Sapphire is the stone people think they know. Say the word and most imagine a deep blue ring, and that image is not wrong, but it is a small part of the picture. Sapphire is the same mineral as ruby, corundum, and it appears in nearly every color there is. It is also, after diamond, the hardest gem material in common use, which is why it has been worn on hands for centuries and still looks new.

Color, and the blue everyone wants

For blue sapphire, the most valuable stones show a vivid, saturated blue that stays even across the gem. Two failures are common. A stone can be so dark that it goes inky and stops returning light, which happens often with material from some sources. Or it can be so pale that it reads as grey-blue rather than true sapphire. The stones that command the highest prices sit confidently between those extremes.

Color also behaves differently inside a sapphire than inside most gems. Many stones show zoning, bands of stronger and weaker color, and how the cutter orients the stone decides whether you see those bands face-up or hide them. That is why cut matters more here than people expect.

Not just blue

Because sapphire is simply corundum that is not red, the family is wide: pink, yellow, green, violet, orange, and colorless. These are called fancy sapphires, and some are rarer than blue. The most celebrated is padparadscha, a delicate blend of pink and orange named after a lotus blossom, which in fine quality can be worth more than an equivalent blue stone. Pink sapphire sits on the boundary with ruby, and exactly where that line is drawn can change a stone's value considerably.

A quick reference

Why origin matters so much

Kashmir sapphires, from a Himalayan deposit largely worked out more than a century ago, have a velvety cornflower blue that the trade has never stopped chasing, and confirmed examples reach extraordinary prices. Burmese stones are prized for a rich royal blue, and Ceylon, now Sri Lanka, has produced fine sapphires continuously for two thousand years. Montana produces distinctive stones closer to home. Origin cannot be judged by eye, and because the premium attached to certain names is so large, it is one of the claims most worth verifying.

The treatment question

Nearly all sapphires sold today have been heated. It is an old and accepted practice that improves color and clarity, and it does not ruin value, though an untreated stone of fine color is considerably rarer and worth more.

Diffusion is the treatment to watch. Here color is driven into the stone at high temperature, sometimes penetrating only the outer skin, turning pale or near-colorless material into something that looks like a fine sapphire. The result can be convincing in a setting and is worth a fraction of the natural stone it imitates. Identifying it is a normal part of how we examine a sapphire. Learn more about treated vs untreated stones

What we see at the counter

Sapphires come across our counter more often than any other colored stone, usually in inherited rings, and the surprises run in both directions. A large, very dark blue stone that the family always called the valuable one is frequently worth less than the smaller, brighter stone beside it. And a plain-looking Ceylon sapphire in a dated setting sometimes turns out to be the piece worth keeping. We tell you which is which.

Buying or selling a sapphire at Coin Mart

Whether you want to buy a fine sapphire, sell one, or understand an inherited piece, we evaluate every stone in front of you, assessing its color, clarity, origin and treatment, and we explain what each means for value. Back to Precious Gemstones →