What qualities* make one pearl more valued than another?

Size: Size speaks for itself; larger simply is more valuable, all other things being equal.

Shape: Round is the rarest and is the most valuable. After that, off-round, oval, drop, buttons, coins, freeform are an example of the progression of the shape. The further from round the lower the value.

	Spherical pearls--Round or near round.
	Symmetrical--Pearls that look the same on each side if you divided them in half.
	Baroque--Irregularly shaped pearls such as crosses & sticks.

Color: White is the universal color. In Asia & the USA pink-white is the ultimate. Other favored natural colors are pink, golden pink, lavender, purple, black, etc. Many pearls are enhanced with dyes, irradiation and other treatments. Dyed pearls have a lesser value than those with natural colors.

GIA classifies pearl color as having 3 characteristics:

	Body color--The dominant overall color of a pearl.
	Overtone--One or more translucent colors that appear over a pearl's body color.
	Orient--Iridescent, rainbow colors shimmering on or just below a pearl's surface.

Luster: This is the most important quality in evaluating the beauty of a pearl. The iridescence, the life of the pearl, the shimmer, glow, and the luminosity of the pearl all come together here. Luster is closely related to orient.

GIA has 4 categories for luster:

	Excellent reflections are bright and pinpoint sharp
	Good reflections are bright but not as sharp, slightly matte finish
	Fair reflections are hazy and blurred
	Poor reflections are diffused and appear chalky and dull

Surface quality: Evenness of the surface, with no undulating undercurrents to distract the eye.

GIA classifies this into 4 categories:

	Clean: Virtually blemish free
	Lightly Blemished: Minor surface irregularities
	Moderately Blemished: Noticeable surface irregularities
	Heavily Blemished: Obvious surface irregularities

Nacre quality: Interrelated with the other two. Thickness & quality of nacre are selling points for fresh water pearls. The quality ranges from acceptable to chalky.

Matching: A brilliant matching pair is more difficult find than a single gem. Look for overall uniformity in color, shape, finish etc. in a strand or suite.

Uniqueness: This can be any unusual combination of the forgoing factors.

Provenance: Previous ownership, from fame to notoriety enhances the value of a pearl. It is the legacy of the pearls detailing its journey from the past to the present. Provenance is related to Branding.

* These qualities apply to all natural and cultivated pearls.

Bibliography

	Akamatsu, Shigeru, Zansheng, Li Tajima, Moses, Thomas M., & Scarratt, Kenneth, "The Current Status of Chinese Freshwater Cultured Pearls", pp.96-113, Gems & Gemology, Summer 2001, Volume XXXVII. GIA, Carlsbad, CA 92008
	GIA Course on Pearls, Carlsbad, CA 92008, 1999
	Joyce, Kristin & Addison, Shellei, Pearls, Ornament & Obsession, Simon & Schuster, New York, NY 10020, 1999
	Landman, Neil H., Mikkelsen, Paula M., Bieler, Rudiger & Bronson, Bennet, Pearls: A Natural History, Harry N Abrams, Inc. in association with The American Museum of Natural History & The Field Museum, New York, NY, 2001