A corundum mineral is called ruby or sapphire, depending on the metallic oxides present which determine the colour. Sapphires come in every colour except red. The red corundum is a ruby.
The most prized blue colour is also known by a flower and is called "cornflower"
The rarest sapphires, "padparadschas" (named after the lotus flower), are orange-pink or pinkish-orange in colour
"Fancy" sapphires" are any "not blue" sapphires
Clarity
Inclusions in sapphire may be composed of fine rutile needles (called silk), which may intersect at 60-degree angles. In such cases, when the gem is cut as a cabochon, a star effect may occur
Inclusions can cause some gems to have milky colouration, this becomes a detriment if it also causes a perceived loss of blue
In top Kashmir sapphires the haziness from inclusions (called sleepiness) acts to diffuse light and colour resulting in even blue coloration
(click on colour to find other gemstones)
TREATMENTS
CUT
Color: Consider all sapphires heat treated unless specifically guaranteed otherwise.
Color: Irradiation can create orange or yellow sapphires out of colorless stones. Color does not stay.
Color: Additional chemical elements can be "diffused" in the stone to enhance/change colors
Clarity: fissures can be filled with glass. This occurs more frequently in rubies than sapphires
Sapphires are mostly cut in traditional pear, round, oval, cushion and emerald cut outlines.
They are sometimes engraved or carved today, though sapphires were sometimes engraved during India's Mughal Era
Care & Collecting
Sapphires are extremely durable due to their hardness and exceptional toughness
As with most gemstones, a soft moistened cloth, or a soft bristle toothbrush may be used to clean the gem
Famous and Influential English Jeweler Edwin Streeter on Sapphires. He led a consortium against Baron Rodthschild for the rights of the Burma Ruby mines.
More on Sapphire. We will add some more themes pertaining to sapphires here. Please bear with us as this is a labour of love, and very very time consuming.
Modern Jeweler has an excellent 4-page review article on Padparadscha Sapphire.
Pala Gems has an amazing article written by Dick Hughes on what constitutes a Sapphire what a Ruby and how colors can confuse you.
A review article of the life of gemologist Robert Crowningshield , the one who wrote the famous 1983 Gem and Gemology Article about Padparadscha Sapphire, and later the 1989 article on the Hope Diamond.