For decades, the Gemological Institute of America (GIA) has taught their students that “gems are specimens of minerals or organic materials used for personal adornment that possess the attributes of beauty, rarity and duralibility.”
The GIA teaches that all three of these attributes must be present – a gem lacking in one or more of these attributes risks losing its status as a gem.
Sri Lanka’s gem industry has a very long and colorful history. Sri Lanka was affectionately known as Ratna-Dweepa which means Gem Island. The name is a reflection of its natural wealth. The blue sapphires from Sri Lanka are known as Ceylon Blue Sapphire. Sapphire derive their name from the Latin word “Sapphirus” meaning blue, and are often referred to as the ‘gem of the heavens’ or the ‘celestial gem’ as their colors mirror the sky at different times of the day. Blue is one of the favorite colors of both men and women and is a color psychologically linked to the emotion of sympathy, calmness and loyalty.
Blue sapphires are traditionally the most coveted members of the sapphire family. Sapphires are one of the toughest gemstones, second in hardness only to Diamonds. Corundum is primarily mined from alluvial deposits and only occasionally from host rock deposits just beneath the earth’s surface. Asterism or the ‘star effect’ is a reflection effect that appears as two or more intersecting bands of light across the surface of a gem. This rare phenomenon is found both in Sapphires and Rubies.
Turquoise is a secondary mineral occurring in veins in association with aluminous, igneous or sedimentary rocks that have undergone considerable alteration, usually in aride regions. It is distinguished from CHRYSOCOLLA by its greater hardness, It can be confused with LAZULITE, variscite, and wardite. A small amount of turquoise replaces bones and other fossil materials. The crystals are rare and minute, usually massive, granular to cryptocrystalline habits as reniform or encrusting masses, or in veins. Distinct crystals have only been found in Campbell County, Virginia, United States.
Alexandrite, a rare variety of Chrysoberyl, is prized for its remarkable optical properties. In daylight, which is rich in shorter wavelengths, it looks bright green. In the warmer, longer-wavelength light or candles or tungsten bulbs, it takes on rich red or brownish-red color. It has therefore been described as ‘Emerald by day, Ruby by night’. The color change is due to chromic oxide, which in alexandrite partially replaces the aluminum oxide that occurs in the chemical composition of Chrysoberyl. Color changes occurs in some types of Sapphire, Tourmaline, Apatite, and many other gemstones, but Alexandrite shows the most dramatic effect.
Chrysoberyl has a variable chemical composition and the this group contains a range of gem-quality minerals. All types of Chrysoberyl are of great hardness, exceeded in this respect only by Diamond, Rubies and Sapphires among the gem minerals. This makes it hard wearing and particularly valuable for jewellery. Chrysoberyl also possesses a relatively high refractive index, giving its gemstones a desirable brilliance.
Cat’s Eye Gemstone describes a polished gem cabochon showing a narrow band of concentrated light goes across the width of the stone. This effect, known as chatoyancy or cat eye effect, is caused by inclusions of thin parallel fibers, fine gemstone minerals that reflect light in a single band. Of all the precious stones displaying the cat eye, cat’s eye Chrysoberyl is the best known.
Eye effect chrysoberyl is stronger and clearer than all gemstones more cat. Although several different types exhibit gemstones effect cat eye, cat’s eye Chrysoberyl only enjoys the privilege of having the name of “cat’s eye” without any prefix. Whenever the term “cat’s eye” is used, it refers to the cat’s eye Chrysoberyl default, unless otherwise specified.
The birthstone for the month of September, the Sapphire comes under the corundum family. Sapphires come in a wide range of colors but are mostly desired for its lush blue shade. In the ancient days, sapphires were believed to protect the wearers from harm and strongly represented honesty and trust.
Sri Lanka, lovingly known as Ratna Deepa is the proud excavator of sapphires of international acclaim. The beauty of these sapphires have been glorified since historical times, by Chinese emperors and Portuguese travelers who adorned these majestic stones in their jewelry. The sapphires produced in Sri Lanka are acclaimed for three factors:
Apart from shades of blue, Ceylon sapphires can be found in colors of yellow, pink, orange, lavender, purple, green and the unmatched padparadscha sapphire. This type of sapphire was named after the lotus flower, as the lotus flower is known as “padparadscha” in Sinhala. All these unique by-products of the Sri Lankan gem industry have created brand recognition throughout the world. This recognition was not established by the gem stone producers, but by the dealers and buyers of these valuable gems.
Certain sapphires, when light bounces off their surface give out a star-like effect. The most recognized star sapphire from Sri Lanka is exhibited in the New York Museum of Natural History. The name was given to star sapphires because when light falls on a cabochon cut sapphire they give a star-like marking effect. This effect is known as asterism and appears in three point star or a six point star.
At one point in time, a milky white corundum also known as gueda, was considered useless for many years and found their spot in the bottoms of fish tanks in homes of gem dealers. The gem dealers in Thailand put an end to this by completing the process nature had left unfinished. The guedas were treated with heat and their undesirable cloudy white color was transformed into a vivid sparkling shade. Although the chemical composition of this end-product is stable, but is sold at a price less than that of an original stone.