How to Judge a Pearl

High quality pearls are highly reflective.

The ancient Greeks believed pearls were formed by lightning striking the ocean. Although modern science clarified the pearl's creation, our captivation with its beauty remains unchanged. Today, cultured pearls dominate the market and include a wide variety of colors, sizes and values. Pearl rating systems, such as the Gemological Institute of America's pearl grading system, take into account several characteristics to determine a pearl's value. Identifying minor distinctions that affect a pearl's value isn't easy, but grading standards help determine the approximate quality of the pearl.

Things You'll Need

• Magnifying glass
• Measuring device

Instructions

1. Examine the shape. Perfectly spherical pearls are the most desirable. To the naked eye, pearls graded as "mostly round" or "off round" appear similar to one another, but comparison under a magnifying class can reveal minor differences.

2. Watch light reflect on the pearl's surface. The strength, smoothness and thickness of a pearl's nacre -- iridescent surface material -- affect its reflective quality. In a high-quality pearl, overhead lights are reflected clearly and have visible definition, similar to a reflection in a mirror. Overhead lights reflecting off the surface of a low-quality pearl appear fuzzy and lack shape or definition.

3. Feel the pearl's surface with your fingers as you examine it under a magnifying glass. High-quality pearls are free of any bumps, blemishes or textured patches, flaws the jewelry world refers to as "inclusions." Even a single, minor abnormality on the surface of an otherwise flawless pearl reduces its value significantly.

4. Measure the diameter of the pearl. Assuming all other measurements of quality are equal, larger pearls command a higher market value. Japanese cultured pearls, known as Akoyas, range in size from 3 mm to 12 mm. South Sea cultured pearls range from 7 mm to 20 mm, making them the most expensive type of pearls available.

Tips & Warnings

• Take your pearl to a jewelry store and compare it against other pearls of similar luster, size, color etc. to determine the quality.

References

• Mikimoto America: Mikimoto Grading System
• Gemological Institute of America: Pearl and Cultured Pearl
• American Pearl: Learn How to Identify Quality
• Perluna Pearls: Grading Systems
• Perluna Perals: Pearl Size