Tuesday, November 1, 2011

Gemstone Series --- Black Star Sapphire

Chemical Make-up:
Sapphire is a form of Aluminium Oxide known as Corundum. Pure Corundum is in fact clear, with other present mineral traces responsible for coloration. In the case of Black Star Sapphires, the black coloration is caused by the prescence of Titanium and Iron impurities.

History & Lore:
The name Corundum is believed to originate from either the Indian word kauruntaka, or the Sanskrit word kurivinda. Sapphire, the name for this particular type of Corundum is taken from the Latin word sapphirus, menaing “blue”.
Star Sapphires are said to be the most powerful Sapphires and are collectively known as the Stones of Destiny. The star shown on the gemstone is said to represent destiny, faith and hope. Star Sapphires have the ability to protect their wearer from physical harm, and from other peoples negative energy and thoughts. Star Sapphires are an aid to meditation and believed to gift the wearer mental clarity and higher wisdom.
It is an extremely hard and a very expensive exercise trying to source natural Star Sapphires that have not been heat-treated as these gems are amongst the most valuable gemstones known today. However, thanks to modern gemstone enhancements and treatments, it is now possible to own wonderful, heat-treated natural Star Sapphires that are both available to meet demand, and priced at a level making this beautiful gemstone attainable / available to most people. Asterism, or stars, are produced using a process known as diffusion. Star Sapphires that have been created this way will often be known as “Linde” Sapphires.

Whilst today's main sources of Sapphire are Africa, Australia, Myanmar (Burma), Sri Lanka (Ceylon), Thailand and the United States (Montana, North Carolina), there are also known Sapphire deposits in Brazil, Cambodia, India, Madagascar, Tanzania and Vietnam.
The highest quality and most desirable Sapphires are those that originate in India, Myanmar (Burma), and Sri Lanka (Ceylon). Sapphires from India and Myanmar (Burma), are highly prized for their pure blue colors and stones from these regions are priced accordingly, often at collectors prices, particularly if there is documentation available to prove the origin of the Sapphire. Sri Lankan (Ceylon) Sapphires are sought after for both their delightful pastel blue and fancy colored variations.
Sapphire is rated at 9 on the Moh's Scale of Hardness and is second only to the Diamond in this regard. Sapphires therefore are perfectly suited to all jewelry purposes / uses and is a very hard-wearing, durable and versatile gemstone suitable for everyday wear.
When thinking of Sapphire, most people immediately think of, and prefer, a blue gemstone. Sapphire is however so much more than just a blue gem and is found in various colors including, black, blues, browns, colorless, pink, orange, peach, purple, voilet, white and yellow. The one color that Sapphire is not is red. Red Corundum is what we know as Ruby. In adition to the single colors, Star Sapphires are also available.
A Star Sapphire is a Sapphire that exhibits a star-like phenomenon (asterism). This is caused by inclusions known as silk. When silk inclusions are abundant the Sapphire becomes translucent or Opaque and this effects the way that the gemstone reflects light. The effect created is a star (usually made up of six rays, but sometimes twelve), that seems to float over the surface of the Sapphire as it is moved.
Black Star Sapphires are sometimes confused with Star Diopside stones, which are far less valuable. There is however one sure-fire way to determine which is which; A Star Diposide will display a star with four rays, whereas a genuine Black Star Sapphire will exhibit a star with six (sometimes twelve), rays. This difference is caused by the physical make-up of each of the stones and the presence of a different number of crystal faces for the light to refract off of.
The quality of Star Sapphires is judged primarily by taking into account the sharpness of the star and the gemstone's overall body color. A natural, untreated Star Sapphire with a very sharp star and a bright blue body color is extremely valuable, very desirable and extremely hard to find.

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