Tones in Sapphires
Tones (shown here in blue) are described as:
Colorless
Extremely Lightt
Very Light
Light
Medium Light
Medium
Medium Dark
Dark
Very Dark
Extremely Dark
Black
White Sapphire, Blue Sapphire, Black Sapphire is same qualification, same origin, different only color. (Please see the description of color above).
Enhancements: Blue sapphire is always heat treated to produce intensify or lighten color and/or improve color uniformity and appearance. Black Sapphire is always heat treated to produce intensify or dark from blue sapphire.
The term "enhancement" is defined to be any treatment process other than cutting and polishing that improves the appearance (color/clarity/phenomena), durability, or availability of a gemstone.
Some gemstone enhancements are less stable than others, meaning that some treatments are temporary. It is the policy of CBS to sell only those gemstones whose enhancements (if any) have good to excellent stability.
Hardness 9.0
Occurrence : Thailand, Vietnam, China, Australia, Lao, Madagasy Republic
Appearance: Although found in a variety of colors, blue sapphire is the color most people think of. When sapphire is mentioned very light to dark (almost inky) shads of blue are found. The more vivid colors (without being too dark) are the most valuable. Black Sapphire is the same qualification with blue sapphire. They have different about color only.
Most of the gemstones listed have a description of it's color and clarity.