Black, also occuring in larger slabs with straight parallel layers of different colors
CLARITY
Translucent to opaque
(click on colour to find other gemstones and jewelry)
TREATMENTS
CUT
Color: Onyx can be dyed in practically all colours, due to its porous nature
Much of the black chalcedony sold on the market is dyed black
In banded material, some bands may be dyed while others remain white
Due to its lack of transparency Onyx is usually cut in cabochons or carved
care
Onyx may be porous, so care must be taken not to immerse the gem in substances that could change its appearance.
A damp, soft cloth, or scrubbing with a soft-bristle toothbrush, are the best ways to clean these two forms of quartz
Carved onyx, such as intaglios or cameos, may be collectible if they have provenance that can be identified as typical of a certain era. Signed gems from a known lapidary artist are also collectible.
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.