Natural Color Sapphire

Sapphire is just one of the varietal names for the mineral corundum, an aluminum oxide (Al2O3). In its purest state, sapphire is colorless, but when impurities get caught up in the crystal growth, the mineral can take on color. A trace amount of iron and titanium produces a blue sapphire. And while Mother Nature creates some spectacular blue sapphires, she doesn’t create enough to satisfy jewelry lovers.

Enhancing otherwise low-quality gems has enabled colored-stone dealers to supply natural sapphire jewelry to the masses. But until recently, for those who prefer what Mother Nature has created, sources have been limited.

Over the past few decades, demand for natural unenhanced blue sapphire has been quiet. So in order to fulfill demand for sapphire jewelry, it’s been easier for producers to enhance nearly everything coming out of the mines, instead of sorting out what now is considered salable unenhanced color. But with recent controversial enhancement techniques being enlisted to produce even greater quantities of beautiful color sapphires, a sudden shift has occurred in the market, leaving gem suppliers with a strong demand for natural color.

History and romance. Sapphires are the jewels of royalty. Sapphire tops Queen Elizabeth’s Imperial State Crown, which has a total of 17 sapphires, more than any other colored gemstone. In her book The Queen’s Jewels: The Personal Collection of Queen Elizabeth II, Leslie Field notes that sapphires play an important role in royal engagement rings. Beginning her account in 1923, Fields writes that Queen Elizabeth [the Queen Mother] “chose a platinum ring set with a large Kashmir sapphire.” The Queen’s brother-in-law, the Duke of Kent, picked out a 7-ct. Kashmir for his bride-to-be, Princess Marina of Greece. In 1935 the Duke of Gloucester gave Lady Alice “a square sapphire.” Alexandra, daughter of the Duke of Kent, chose a large oval sapphire ring and wore it along with an oval star sapphire that she inherited from her mother. Princess Anne was given a round sapphire by Captain Mark Phillips upon their engagement in 1973. And in 1981, Prince Charles gave Lady Diana Spencer a large oval sapphire chosen from a tray of rings. (According to reports, Lady Diana said it was not the largest in the selection.)

Color. Natural-color sapphires occur in every color of the rainbow, but historically the most important color for sapphire is blue, also called royal blue.

Sapphire blue ranges from very light or pale to very dark, also called “inky.” Secondary hue can range from greenish-blue to purplish-blue to violet-blue. Of course, as with most gems, the more pure the hue, the more valuable the stone.

Since mining deposits are unique, color also may be described using country of origin. For example, a Thai sapphire is typically dark blue; an Australian sapphire is typically very dark, often greenish-blue; and a Ceylon stone is quite often a light to medium blue. Burmese blues are typically a rich intense medium-dark blue. Last but not least, and top of the mark, is the color of a Kashmir sapphire, called “cornflower”—a saturated, vivid, slightly milky (sometimes called “velvety”) and somewhat “electric” blue.

Country of origin. The most prized Kashmir sapphire is found in the Great Himalayan region of the disputed land between India and Pakistan. Sapphires have been mined there for over a century, but the late 1800s saw the boom and bust. Sri Lanka, Burma, and Yogo Gulch, Mont., produce exceptional stones with saturated color, with Burma the leading producer of the three. Sri Lanka (formerly known as Ceylon) and Yogo Gulch have the distinction of producing Kashmir-like colors but, unfortunately, not in great quantities.

Sri Lanka, the large island located off the southern tip of India, has been a source of sapphires for thousands of years. (The name Ceylon means “the place of jewels.”) It produces a vast quantity of gems, sapphire included. Because of its distinctive lighter, brighter color, and because so much of it made its way into the market in the early to mid 1900s, the name “Ceylon sapphire” became quite popular.

Madagascar produces a large amount of sapphire as well, and it’s been compared to Sri Lankan material in both quality and quantity. “Montana sapphire” refers to deposits of Montana sapphire other than Yogo. Yogos have naturally saturated color, whereas all other Montana sapphires typically get their color through heat treatment.

Thai and Cambodian sapphires are commonly spoken of as one general locality, and they have similar colors. Tanzanian sapphire comes from both the northern Umba River Valley and the Southern Tunduru and Songea tracts. Malawi, where 1950s sapphire deposits have been recently reported on, is directly across Lake Malawi from the Songea region of Tanzania. East African sapphires are mostly of sufficient color to be sold as natural color origin.

Naming the country of origin can affect a sapphire’s salability. Inclusions pinpoint the exact origin of the stone, and natural-color gems that contain inclusions are more likely to be labeled with a country of origin than those without inclusions. Enhanced sapphires usually are not labeled with a country of origin since many identifiable inclusions are destroyed during the enhancement process.

A gem lab report that states natural-color origin is preferred, especially since the Madagascan material needs only subtle heat for enhancement, which may not affect inclusions as obviously as it does when using higher temperatures to enhance Thai, Cambodian, and Sri Lankan sapphires.

Prices. According to The Guide , fine-quality unheated Burma sapphires of 2 cts. to 3 cts. can be priced anywhere from $1,500 to $2,500 per carat. In extra-fine quality, prices will top out at approximately $4,200 per carat. Yogo and Kashmir stones reportedly are priced on an individual basis. Sapphires from Burma, Yogo, and Kashmir are assumed to be natural color because these mines can produce exceptional color without any outside help. Stones from other localities are presumed to be heated, so when pricing natural color, a small percentage above list price should be considered. Extra-fine Madagascar material, along with sapphires from localities other than Yogo, is priced in the region of $1,800 to $3,300 per carat. The price difference between unheated and traditionally heated sapphires is reportedly in the region of 15% to 25% for fine-quality gems; for exceptional gems, the price gap can be higher.

Care and cleaning. Sapphire has a Mohs hardness of nine, so it wears well and can take most forms of punishment. But remember that Madagascan sapphire requires only a small amount of heat to possibly alter its color, so heat at the bench should be avoided for a natural-color Madagascar sapphire.

Recommended reading. For more information, see Ruby & Sapphire by Richard W. Hughes, RWH Publishing; and Gems by Robert Webster and Peter Read, fifth edition, 2002, Butterworth-Heinemann.

Special thanks to Richard Hughes, Pala International, Fallbrook, Calif.