Sapphire Gem: Sources and Types

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Sapphire, a September Birthstone,  is a variety of the mineral Corundum and is one of the cardinal gems along with Diamond, Ruby and Emerald. Commonly used in jewelry, it is naturally found in rock formations or certain alluvial deposits. It is also manufactured in labs for decorative or industrial purposes. Commercial mining of Sapphire is carried out in the following countries: Australia, Cambodia, Colombia, Kenya, Madagascar, Nepal, Sri Lanka, Tanzania, USA, Afghanistan, Myanmar, China, India, Laos, Malawi, Nigeria, Thailand, Vietnam and Pakistan. The “Star of India”, “star of Bombay” and “the Logan” Sapphires originate from the Sri Lankan mines. The world’s first Sapphire mines are situated in Kashmir (India) and Sri Lanka. The gem deposits here occur in gemmiferous or gem-bearing gravels found in ancient alluvial deposits or along river beds. These river gravels also contain quartz and ruby. The Sapphire deposits also occur within pegmatite and metamorphic rocks. The mining processes in these sites are small scale, non-mechanized operations. It involves workers who excavate the gravels from a 4 or 5 feet deep pit. The specimens are then washed and sifted through a sieve made of bamboo strips.

Types of September Birthstone – Sapphire

Natural Sapphire: It normally comes is a pinkish orange color and the value of the gemstone depends on the clarity, cut, color and size. The other colors of a natural Sapphire are blue and colorless. They are mostly found in Thailand, China, East Africa, Eastern Australia and in North America (mostly in Montana). The gem is often found in the same locations as Ruby but in every site, one gemstone is usually more available than the other.

Blue Sapphire: A gem color is defined by three components: saturation (brightness), hue (color) and tone (the darkness or lightness of a color). The Blue Sapphire’s value depends on the purity of its primary hue (blue).  Violet, purple and green are considered as the secondary hues in the gem. Purple and violet add to the total value of the gemstone whereas green is considered to be a negative factor.

Star Sapphire: This type features a star like effect called “asterism” from within the stone. It contains certain needle-like inclusions in the crystal that give rise to a star-shaped pattern. The mineral inclusions are usually titanium dioxide. The Star Sapphire is typically cut in a cabochon (cut convexly without facets) shape with the center near the top of the dome.

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