Standard color light to medium yellow to yellowish green, greyish green, brown to yellow-brown to light blueish yellow to greenish but several other types have color effects:
Color change effect in Alexandrite is primarily red to green, depending on whether it is viewed in lamplight or daylight. These two colors were coincidentally the royal colors of the Russian Czars, hence its popularity in old Russia
Cat's eye Chrysoberyl is yellow to yellowish green; greyish green; brown to brownish yellow
Clarity
Non-phenomenal chrysoberyl is transparent to semi-transparent, comprising a range of colours.
The alexandrite variety contains gems that vary from transparent to semi transparent, and whose colour appears different depending on the light it is viewed in.
Cat's eye chrysoberyl is opaque to semi-transparent, containing minute parallel inclusions that cause chatoyancy.
(click on colour to find other gemstones)
TREATMENTS
CUT
No known treatments in significant numbers
One case known of brown cat's eye chrysoberyls in the 1990's which was irradiated in a nuclear facility to deepen the brown colors
Normal Chrysoberyls and alexandrites occur in a variety of standard cuts
Cat's eye chrysoberyl occurs in cabochon due to the nature of the effect (chatoyancy)
Care & Collecting
With excellent hardness and toughness, chrysoberyls of all types are extremely resilient for use in jewelry and may be worn under daily conditions.
Alexandrites and cat's eye chrysoberyls are quite rare to begin with and as such highly collectible due to their exotic, phenomenal qualities. A premium is placed on gems that contain strong colour change qualities, since with alexandrites a predominantly "muddy" mix of greens, browns and reds tends to be the norm, resulting in a vague colour change.
With cat's eyes, a strong, sharp and unwavering silvery line that is visible from girdle-to-girdle is highly desirable, accompanied by rich green, yellow or brown colours.
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.