Pearls

Pearls are extracted from oyster shells and in the ancient civilizations, these were considered to have magical powers. Pearls can be worn even without any polishing and treatments. Natural Pearls or Basara Pearls are formed in molluscs in the deep layers of the oceans. However, these days, cultured pearls are widely available in the market. Cultured Pearls are the imitation of natural pearls and made by surgically inserting a mantle tissue and a bead nucleus into an oyster. This oyster is re-harvested in the sea where the pearls are formed. The quality standards of natural and Cultured Pearls are not the same. Some of the Cultured Pearls are south sea pearl and Tahitian Pearls. These are bigger in size than the natural pearls.

Blue Sapphire (Neelam)

The blue color of Blue Sapphire represents nobility, truth, sincerity and faithfulness. It also reflects the shades of sky. Blue Sapphire is available in the range of very light blue to very dark violates to greenish blue shades. Although the velvety bluish to violates blue in medium tones are considered to be the most valuable ones. According to a GIA source, 95% of blue sapphires are heated or lattice diffused to improve their color and clarity. However, untreated sapphires are the most costly and exclusive of the lot in the market. Chemically this stone is composed of aluminum oxide, iron and titanium.

Some other specifications are as follows:

Ø  Species: Corundum

Ø  Refractive index: 1.762-1.770 ( 0.009/-0.005)

Ø  Specific gravity: 4.00 ( 0.10 /-0.05)

Ø  Melting point: 2050 C (Approx)

Ø  Hardness: Resistance to scratching, 9 on the Mohs scale

Ø  Toughness: Resistance to breaking and chipping, (Usually excellent) but large fractures can make the stone brittle

Ø  Heat: Heat causes change in color & clarity and can damage fracture filling

Ø  Light: Fracture filling may dry out or alter under intense light

Ø  Chemicals: Can harm the fillings in fracture filled stones

Blue Sapphire is mostly found in Kashmir (India). Other sources are countries like Burma, Sri Lanka, Australia, Madagascar, Nigeria and United States.

Following are the treatments done on these stones:

Ø  Heat Treatment: Heating to a very high temperature to change its appearance

Ø  Surface diffusion: Heating at a very temperature in presence of coloring agents so that the chemicals penetrate the stone

Ø  Fracture filling: in order to conceal the fractures, stones are filled with epoxy resins, glass or lead glass.

Synthetic Blue Sapphires are made by the process of flame fusion, flux, hydrothermal and floating zone. These synthetic versions are also available in the market however, these can be distinguished only by inclusion (magnification). The process of cleaning and caring these stones are as follows:

Ø  Ultrasonic cleaning: Usually safe, but not for fracture filled stones

Ø  Steam cleaning: Usually safe, but not for fracture filled stones

Ø  Warm soapy water: Safe, but strong detergents should be avoided