Pearl Grading | Luster

Pearl Grading System

Pearl grading is very similar to the 4C's of diamond grading in that it takes into consideration several categories of qualitative comparisons. The pearl grading system consists of five main parts. They are:

• 1. Luster
• 2. Shape
• 3. Color
• 4. Surface
• 5. Size

1. Luster (Lustre)

Since a very 'lustrous' baroque pearl is probably more desirable than a round milky pearl, lustre is generally considered to be one of the most important aspects of a pearl's grading and valuation. The quality of a pearl's nacre gives the "lustrous" quality for which pearls are valued. Luster refers to how "shiny" or dull a pearls is:

• Low lustre: Pearls surface appears chalky and/or "milky."
• High lustre: Pearl surface reflect light and show mirror-like reflections.

On a bright and sunny day, place your pearls on a white piece of paper or white cloth near a window, but do not place the pearls in direct sunlight. See how the pearls reflect the shape of the window frame. The clearer and more well defined the window's reflection, the more lustrous the pearl.

A Pearl's luster will be dependent on the quality of care given to the oyster in its early growing stages. The better the pearl producer cares for the health of his molluscs, the higher the pearl quality.

As with natural pearls, higher-quality 'lustrous pearls' make up only a fraction of the pearls available on the market, and they will command the highest prices.