4*8mm Natural Marquise black Sapphire in AA Grade

1 the shining is the best. 2 excellent quality and best price 3 large stock 4 remarkable hardness

Forever Star Jewelry, is one of the professional jewelry and gemstones manufacturers in Panyu, Guangzhou, China.

1 Quality: We have strict quality controller department to ensure the professional characteristic and top rate of our products

2 Stone: we can offer a wide range of gemstones products, synthetic and natural gemstones

3 Price: very competitive prices with large stock

4 welcome to inquiry at any time!

Name	Black sapphire
Color	Pure black color: The stone color is very deep blue, so it looks black. but it is not black as hair or black agate. the shining is the best.
Category	Oxide mineral
Chemical formula	aluminium oxide, Al2O3
Crystal habit	massive and granular
Specific gravity	3.95–4.03
Luster	nice
Treatment	treated
Hardness	9
Clarity	Opaque
Grade	AAA
Melting point	2030–2050 ° c

Sapphires may be treated by several methods to enhance and improve their clarity and color. It is common practice to heat natural sapphires to improve or enhance color. This is done by heating the sapphires in ovens to temperatures between 500 and 1800 °C for several hours, or by heating in a nitrogen-deficient atmosphere oven for seven days or more. Upon heating, the stone becomes more blue in color but loses some of the rutile inclusions.

4*8mm Natural Marquise black Sapphire in AA Grade