Pearl Education

Cultured and Natural Pearl Weight Descriptions

Pearl weight is expressed in carats or grains when describing natural pearls, or kilograms, kan or momme when describing cultured pearls.

When Is Pearl Weight Used Instead of Size?

Most of the time, pearls are described primarily in terms of their size (diameter) and expressed in millimeters. Weight is typically only described within the wholesale trade or when dealing in rare wild pearls such as abalone or conch.

How to Weigh Pearls
Natural...

Grading South Sea and Tahitian Pearls

While there is no internationally recognized number or letter system for pearl grading, there are best-grading practices that are accepted and recognized by all professional pearl dealers within the industry. Understanding grading attributes and quality characteristics of South Sea and Tahitian pearls is imperative to properly shop and compare.

Pearl Grades: Combining Seven Different Value Factors

As pearls have many differing value factors such as...

Mother-of-Pearl Defined

Mother-of-Pearl (MOP for short) or Nacre (as it is also known) is the iridescent coating on the inside of some mollusk species which is composed of aragonite and calcite, both being calcium carbonate polymorphs. MOP also contains water and binding proteins secreted by the mollusks, the most important being conchiolin.

Mother-of-pearl is also the primary material used in pearl nucleus manufacturing. MOP beads are still the most common nucleus (core) used to produce...

Marine Pearl Farming Defined
Pearl farming is the industry responsible for growing farm-raised pearl mollusks and producing cultured pearls. These cultured pearls make up nearly 100% of the pearls sold today.

What Is Pearl Farming?

Cultured pearls are grown on what are known as pearl farms. Depending on the variety of mollusk employed at the farm, these will be located inside protected bays or in channels or in lakes, ponds or streams (for pearly freshwater mussels). In this chapter we...

The Pearl Harvest
The pearl harvest is the pay-off for years of investment and arduous work. The harvest most-often happens during the winter months as the host mollusks' metabolism slows and nacre platelets become thinner as deposition decreases. This has proven to increase the luster upon harvest.



Pearl Production Times Vary

Cultured pearls are harvested from the pearl farms after a period that may stretch from 8 months to 6 years. Akoya pearls are typically cultured from 8 months to 2...

The Proper Pearl Nucleus

A pearl nucleus is usually made using freshwater mussel shells that has been cut and ground into a polished, spherical bead. Other nuclei do exist, these have been produced from other marine shells, such as from the large black and silver-lipped pearl oysters and from Bironite TM.

Nacre Deposition will occur over any Solid Object

An oyster's "pearl sac" will secrete nacre over nearly any solid object. This has led to countless attempts to nucleate oysters with...