Pearl Valuation Factors

How pearls are categorized and sorted

LUSTER

Pearls have a rich inner glow that seems to come from deep within.  That’s luster. It’s an effect caused by light reflecting and diffusing through the layers of nacre. High luster tends to make a pearl more valuable. As a test, stand with a beam of bright light behind you, hold a large, fine-quality cultured pearl close to your face. You’ll see the light reflected and yourself. Detailed Explanation

ORIENT

The play of light refracted through many layers of concentric nacre creates the orient – the iridescence of a pearl that sometimes creates a rainbow effect. The Latin word oriens means “the rising of the sun”. Detailed Explanation

NACRE

A pearl and the inside surface of the shell of its parent oyster or mussel are made of nacre.  Layer by layer, this crystalline substance builds up around a small bead or piece of shell (the nucleus) implanted in the culturing process. The thicker the nacre, the more lustrous and durable the pearl is.

Through a microscope, the surface nacre of a cultured pearl looks like a lunar landscape – irregular “fingerprints” that are unique.

To check if a new pearl is “real”, rub it gently against your front teeth. If it feels bumpy or gritty, it’s probably a genuine cultured pearl. A simulated or imitation pearl will glide over the teeth and feel like plastic.

Detailed Explanation

SIZE

Most pearls are measured by their diameter, irregularly shaped pearls by their width and sometimes length. The standard of measurement is the millimeter (mm).  From less than 1mm (seed pearls) to over 20mm (South Seas  &  sometimes Tahitians), the size of a cultured pearl depends mainly on the size of the parent oyster or mussel, the size of the implant nucleus, and how long it is cultivated. All factors being equal, the larger the pearl, the greater the value. For instance, a Mabe cultured pearl has a wide diameter but is a “half-pearl” with a flat bottom. Its value is much less than a large, round South Sea cultured pearl of similar quality.

Some average sizes:

• Akoya 2-10mm
• Tahhitian 8-16mm
• South Sea (White & Golden) 8-18mm
• Keshi 1-10mm
• Mabe 12-25mm

(One millimeter = 1/25 inch)

SHAPE

Cultured pearls come in an almost infinite variety of shapes, partly determined by the shape of the nucleus around which the pearl is formed.  Round pearls are the traditional favorites.  A pearl with an irregular shape is called Baroque.  The popular pear and teardrop pearls are Semi-Baroque - irregular but symmetrical.  No matter what the shape, it falls into one of five main categories.

Round: Symmetrical spheres. Variation rate of diameter – 2% or less.

Semi-Round: Spherical. Variation rate of diameter – 2-5%.

Baroque: Irregular

Semi-Baroque: (Drop Button Oval Pear) Partially symmetrical. One axis of revolution or more.

Circled: (Primarily Tahitian & South Sea pearls) Streaks, ridges or rings in regular formation on the upper third (minimum) of surface.

To test the roundness of a pearl, place it on a smooth, sloped surface. The rounder the pearl, the straighter and more easily it rolls.

COLOR

From opaline white to anthracite black, the palest pastels to vibrant hues, pearls come in almost every color and shade. The finest have a subtle interplay of colors – the primary body color plus delicate overtones. One of the rarest colors today is the rich warm gold of South Sea pearls from the Philippines.

SURFACE

What’s called “cleanliness” affects the value of a pearl. Generally, the fewer blemishes the better. Tiny irregularities are acceptable and can be a test of authenticity.

WEIGHT

The value of a pearl is seldom judged by weight.  Single pearls are weighed by grains or carats.  One grain = 50 milligrams.  Four grains = one carat.  In the wholesale market, strands of cultured pearls are often  sold by the "momme" (pronounced moh-may).

At Mastoloni Pearls the weight measure we use for loose pearls and pearl necklaces (typically South Sea and Tahitian) is momme. Momme is a weight measure developed by the Japanese centuries ago.  Today, momme weight is still the standard unit of measure we use to communicate with our Far East pearl suppliers and pearl farmers. Momme is pronounced much like the word "mummy." One momme = 1/1000 kan.  Reluctant to give up tradition, in 1891, the Japanese government formalized the kan measure as being exactly 1 kan = 3.75 kilograms or 8.28 pounds.  Hence, 1 momme = 3.75 grams or 3750 milligrams.

In the United States, 19th – 20th centuries, through trade with Japan in silk cloth the momme became a unit indicating the quality of silk cloth, = the weight in pounds of 100 yards of silk cloth 45 inches wide.

One carat = 4 grains = 200 milligrams = 1/5 gram
One grain = 1/4 carat = 50 milligrams = 1/20 gram
One momme = 18.75 carat = 3750 milligrams = 3.75 grams
One kan = 18,750 carat = 3750 grams = 3.75 kilos

Why do we show momme weight?  At Mastoloni Pearls it is important for our customers to know the momme weight of a south sea or tahitian necklace as size (mm) can mask value.

PEARL COHERENCE

Each cultured pearl is unique. To create jewelry, pearls that complement or match each other are selected in a process that can take years. Thousands of pearls may be rejected to find the desired combination. When the results are successful, the piece has balance and works as a harmonious whole. It has coherence.

"The Pearl" Video

These three video will take you into the details of pearls.  From its mystic origins to today, the entire process of pearls cultivation, pearls harvesting, pearls sorting, pearls grading and current fashions are discussed in this wonderful and educational thre part video set.  Disciver the majestic beauty of pearls.  Enjoy the show!

"The Pearl" (Part 1)

"The Pearl" (Part 2)

"The Pearl" (Part 3)

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