Ruby guide

Ruby/Corundum In Sanskrit texts honor ruby with the word "ratnaraj,” meaning king of precious stones. The term ruby is reserved for corundums of a red color, with other colors called sapphire. Large, fine-quality rubies are extremely rare and valuable. The highest price per carat ever paid for a ruby was set on February 15, 2006, when Laurence Graff, a London jeweler, paid a record $425,000 per carat ($3.6 million) for an 8.62-ct. ruby, set in a Bulgari ring, at a Christie’s auction in St. Moritz.

COLOR

Color range............	Red, pinkish Red, purplish Red, to orangy Red
Finest color,...........	Deep pure, vivid Red, without being too light or too dark. Often describe as "pigeon blood" or "burmese color."
Pink, Purple, and Orange sapphire:	Stones with dominant color Pink, Purple, or Orange are called pink, purple, or orange sapphire. In some Asian countries, these stones sold as rubies. It's important to keep such regional trade practice variations in mind if you work in different markets.

DURABILITY

Hardness (Mohs scale)	9
Toughness	Excellent
Stability	Environmental Factor	Reaction
	Heat	Stable, except fracture- or cavity- filled stones
	Light	Stable, except irradiated stones fade quickly
	Chemical	Avoid boric acid powder

SOURCES/ORIGINS

Major	Other
Kenya, Madagascar, Myanmar (Burma) Tanzania, Thailand	Afghanistan, Sri Lanka, Vietnam,

ENHANCHMENTS

Type	Purpose	Stability	Prevalence	Detection
Heat	Most commonly improves color and/or clarity appearance	Stable	Very common (experts estimate that up to 95%)	May be detectable by a trained gemologist. Read more>
Diffusion (high temperature with chemical element(s) from external source)	Improves color	Stable, some can be damaged if the stone is recut	Common	Detectable by a trained gemologist. Read more>
Fracture-filling (with glass or epoxy)	Improves clarity appearance	Fair. Heat and chemicals can damage	Common	Detectable by a trained gemologist. Read more>
Cavity-filling	Improves clarity appearance by hiding cavities	Fair. Heat and chemicals can damage	Occasional	Detectable by a trained gemologist. Read more>

CARE and CLEANING

Type of Cleaning	Advisability
Ultrasonic cleaning	Safe, but never for fracture- or cavity-filled stones
Steam cleaning	Safe, but never for fracture- or cavity-filled stones
Warm, soapy water	Safe

Alternatives	Naturals	Man made
	Almandite garnet, Pyrope garnet,	Synthetic ruby
	Rhodolite garnet, Spinel, Tourmaline	Synthetic spinel

Do you know?	Rubies generally look best viewed with incandescent light or daylight. Avoid fluorescent tubes, which have virtually no output in the red of the spectrum, and so cause ruby to appear grayish.
	Ruby is the birthstone for July.
	In the case of some rubies, extremely fine silk throughout the stone can actually enhance the value.
	Ruby is the world‘s most expensive gem. But like all gem materials, low-quality pieces may be available for a few dollars per carat.
	Large rubies of fine quality are far more rare than large sapphires of equal quality. Certainly, any untreated ruby of fine quality larger than two carats is a rare stone; untreated rubies of fine quality above five carats are world-class pieces.

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