Both Princess Diana and Princess Ann have sapphire engagement rings--examples of sapphire long being a favorite of royalty--including Charles V (1364) of France--to preserve them from harm. According to the Bible, sapphires were in the Garden of Eden and something like them will be in the heavenly Eden -- because of their high polish. Today, sapphire is the traditional birthstone for September.

The peaceful, heavenly hues of blue stones were often thought to calm the mind, body, and spirit. And sapphires have been credited with many medicinal and spiritual powers; including an antidote for poisonous bites -- so Texans really need to wear them!

Sapphires have superior durability. And durability is more than just hardness--like the difference between a banana and an ice cube -- but sapphires are hard as well -- right after diamonds on the Mohs scale.

Many people think all sapphires are blue. But sapphires are actually corundum that are any color except red. Red varieties are called rubies. Sapphires range in color from violet--the most difficult to distinguish from a ruby -- to blue, green, yellow, orange, pink, and purple. The general term for any color except blue is "Fancy." The GIA is shying away from using "place" names in describing color. But you can still use fanciful language when selling the beauty of color. For example, the term "padparadscha" ("pad" for short), meaning "lotus color," is used to describe sapphires having a rare pinkish-orange color. The most desired sapphire color is pure cornflower (not cauliflower) blue. Small differences in any of the color components--hue, tone, and saturation--can have an important impact on value.

Probably the most important enhancement besides that designed to improve color is that used to improve clarity. Controlled heating and cooling can dissolve the slender rutile needles (called silk) right into the crystal structure to improve the clarity. Although large sapphires are rare, the Smithsonian has the Logan sapphire--a 423 carat blue stone from Sri Lanka--together with several other large stones, including a 92.60 carat yellow Burmese. And large beautiful sapphires also can be seen in museums in New York City and Toronto.

The most important sapphire sources are Kashmir, Sri Lanka, Thailand, Australia--and PSU, deep in the heart of Texas -- and the Yogo Gulch in Montana. Other sources include Burma, Colombia, Kampuchea (Cambodia), Kenya, and Tanzania.

Kashmir is the quintessential sapphire source! Blue sapphire from Kashmir has always been very highly regarded because of its superb cornflower blue color. The deposits were located in 1881. Almost all Kashmir sapphires show zoning, and this is one of the ways in which they can be identified. The zoning is associated with very small layers of liquid inclusions that give the velvety or sleepy appearance. The Kashmir mines have not been operating, at least officially, since 1983 and any crystals recovered were found by the indigenous population who were forbidden to engage in mining or in gem trading.

Sri Lanka is the penultimate sapphire source. The main deposits are in Ratnapura, Pelmadulla, Balangoda and Rakwana. The milky white sapphires, locally known as geuda, are heated in Thailand to give a fine blue color. Sri Lanka is also the major source for yellow, violet and orange (Padparadscha) sapphires.

Thailand is today's leading source of sapphire. But mining is not the reason. Instead, heating accounts for the large volume of stones sold. The Thais have developed elaborate procedures for "lightening Australian and darkening Sri Lankan" sapphires. Costs for the rough, mining, and cutting all fall behind the cost of the fuel needed to maintain the ovens used to "cook" sapphire. Black star sapphire is mined principally in Thailand.

The sapphire deposits of Montana produced a large quantity of industrial grade material. Gem material was also found, and an estimated $25 million has been recovered from the Yogo Gulch mines. Lately the Yogo mining companies have fallen on hard times and filed for bankruptcy. This was partly because of the sale of "treated" sapphire from Thailand, as "natural Yogo sapphire." Do not expect Yogo to be "natural" untreated sapphire.

The main sapphire-bearing rocks are marble, basalt, or pegmatite, mined mainly from alluvial deposits or deposits formed by weathering. Sapphires rarely are mined from the primary rock. Corundum stones (sapphire and ruby) are gems with the smallest hexagonal unit cells. They resemble boxes with hex ends and rectangle sides. This structure can be seen distinctly then viewed under a gemscope. They have four axes -- three that intersect each other at 60 degree angles, and one perpendicular to the other three. In the spectrascope, sapphire shows iron absorption in a wide band from 450-460 nm, with a fainter band to 470 nm.

When a sapphire shows asterism, it is called a "star" sapphire. The star is seen in cabochon cut sapphires (rounded, dome-shaped cuts) as several movable arms, or rays of white light, radiating from the center. Black star sapphires are usually cut in a flat cabochon. And they need to be worn with more care than other sapphires to prevent separation between their "twinning" planes. "Twinning" occurs when alternating layers grow in different directions.

Prices of almost all sapphires have increased only slightly since our Tenth Edition Catalog was printed. Kashmir sapphires continue to command the highest prices. In 1981 at the Tucson gem show, a thirty carat gem Kashmir sold for $ 1,000,000. But prices of Ceylon (Sri Lanka) sapphires have increased dramatically in the last five years. Also, there has been a significant increase in prices of stones of three carats and larger.

DIFFUSED SAPPHIRE

I'll bet you've noticed the new sapphire on the market know as Diffused Sapphire. No. Diffused is not a geographical location like Ceylon, Thailand, or Burma. Diffused is a process where man takes colorless or pale corrundum and treats it with elements that give sapphires their blue color. The colorless or pale stones they once were are now beautiful rich blue stones that anyone would love to possess. They even sometimes rival the finest blue Ceylon color. The diffused sapphires are quite durable as long as they are never repolished or recut. The treatment to produce blue is only .25 to .50 millimeter into the stone's surface. Therefore, recutting or repolishing would remove the enhanced color. But it does not make the surface any softer than any other natural sapphire.The prices on these diffused stones are very reasonable, running about 1/6th the price of natural colored sapphire of similar color.

Sapphires are comprised mainly of aluminum oxide, but titanium and iron are the trace elements that give natural colored sapphires their color. For years almost all sapphire rough has been heat treated. The addition of heat burns out impurities and allows the trace elements to expand improving the color. Then the rough material is cut into faceted or cab gems.