Ruby and blue sapphire - along with sapphires in orange, yellow, green, purple, and pink hues - are special variants of the colorless mineral aluminum oxide, also known as corundum. Formed under unique conditions millions of years ago deep in the earth’s crust, the gems owe their vivid colors to tiny amounts of elemental impurities incorporated into their crystal structure. Long prized as luxury goods, natural, untreated sapphires are even more of a rarity than is generally understood. Unheated and free from chemical enhancement, these gems emerged from the earth already endowed with rich colors and high transparency, distinct from the cooked, commercial stones that make up 96% of the supply. Extraordinary in color, clarity, size, and rarity, great blue sapphires from three renowned historic sources in Asia - Kashmir, Burma-Myanmar, Ceylon-Sri Lanka - are uniquely appealing as eye-catching rings, and have special regional characteristics that have long been treasured by the knowledgable collectors who covet them.
Left: Natural sapphire crystal, Natural History Museum, Los Angeles; Right: A Ceylon “sapphire” before treatment: the majority of such crystals are heated in a chemical slurry to create blue color and increase transparency
KASHMIR
In the late 19th century, Kashmir was the source of legendary sapphires that emanate a lustrous, “sleepy” blue in any kind of light. Discovered in 1882 by a trader traveling through a remote valley that was snowbound for nine months a year, the gem cache had been uncovered by a mini landslide. The big stones were easily plucked from the mountainside where they sat “as thick as plums in pudding,” some “the size of cricket balls.” Despite the hostile climate and altitude, this “Old Mine” deposit was worked by agents of the Maharajah of Kashmir until its sudden depletion in 1887.
Summertime view of valley (elev. 17,000 feet), Kashmir, nearby site of 1880s mine
These ne-plus-ultra sapphires have unique properties . A subtle, velvety “silk” of included mineral needles helps throw light around the interior of the gems, creating an even, rich blue. Thanks to the nanoscopic size of the silk, it doesn’t diminish the Kashmirs’ clarity. In the 1930s, an English company worked a nearby area in the valley briefly, with disappointing results. Nonetheless, fascination with Kashmir as a source of gems remains strong. Cap Beesley, a Yale geoscientist, is the only professional known to have approached the site in recent years to prospect for new gems. In 1994, Beesley trekked deep inside insurgent-held territory where the mine site lies. He reluctantly concluded that the outlook for new discoveries was not hopeful, suggesting Kashmirs will only become increasingly rare.
BURMA - MYANMAR
Left: The internal world of Burma sapphires: Short, dense rutile needles help distribute light and color evenly; Right: AGL No-Heat Burma Sapphire Ring, 9.95 carats
Another source of the most prized sapphires is Burma, a region also blessed with the world’s most coveted rubies. Its rulers have controlled sapphire and ruby production, guarding it from outsiders for centuries. Top Burma sapphires exhibit a saturated, royal blue, with slight violet overtones that offer a lively brightness. Color tends to be well distributed by short dense needles of included rutile that help scatter light throughout the body of the stone. Burma sapphires exhibit a “robust brilliance” and high clarity. While rare, Burma sapphires can occur in impressive size. Natural, unheated material is in very short supply, however, and new sources are reportedly not coming to light.
CEYLON - SRI LANKA
Left: Cartier AGL Ceylon Sapphire Ring, 10.98 carats; Right: AGL No-Heat “Classic Ceylon” Sapphire, 2.95 carats
The gem gravels of Ceylon may be the oldest source of top sapphires in the world. (Fig. 9) Ceylon sapphires have been found in ancient Egyptian jewelry, attesting to the existence of broad trade networks connecting the earliest luxury-loving civilizations. Less saturated than Burmese sapphires, the “Classic” hue is a lighter, sweeter blue. (Fig. 10) Due to the color zoning that these stones can exhibit, skilled cutting is key in enhancing their beauty. Cutting colored stones is far less systematic than diamond cutting, requiring both specialized expertise in the characteristics of each region, and a feeling for the art. A highly skilled cutter maximizes the potential for beauty of each crystal, prioritizing the concentration of color, maximizing light reflection to the eye, preserving weight, and maintaining a graceful form. The gorgeous blue of a “Classic Ceylon” color designation is highly sought after by connoisseurs.
VALUING TOP NATURAL SAPPHIRES: THE ESSENTIAL LABORATORY “ORIGIN” REPORT
These three top regions represent points on the outer ring of the Indian Ocean orogenic (mountain-building) zone. (Fig. 12) Since there is overlap in the geological conditions in which they form, the traditional means of determining a gem’s origin - examining inclusions - has given way to more reliable scientific analysis. By analyzing natural, untreated stones from known sources for decades, independent, research institutions such as American Gemological Laboratory (AGL), founded by Cap Beesley and run by Christopher Smith, have built proprietary databases of spectrographic information that serve as an authoritative basis on which to determine sapphire origin. Given the rising desirability of all these natural sapphires, “region of origin” reports add to the fascination of these gems’ special history, and supports their authenticity as artworks of nature.
Kashmir, Burma-Myanmar, Ceylon-Sri Lanka: The most valuable deposits are all part of the same Indian Ocean mountain-building zone
