Pearl Quality Factors

Collection of pearls
This collection includes a palette of beautiful cultured pearls. Besides round golden white loose cultured pearls, there’s a strand of well-matched round whites and a strand of oval pastel colours.
The qualities that determine the overall value of a natural or cultured pearl or a piece of pearl jewellery are size, shape, colour, lustre, surface quality, nacre quality, and—for jewellery with two or more pearls—matching.

Size: When other value factors are equal, larger pearls are rarer and more valuable than smaller pearls of the same type.

The mollusc that produces South Sea cultured pearls is larger than the mollusc that
produces Japanese saltwater cultured pearls. This leads to greater potential for larger
sizes. - Gift of Bob & Maria Pratsch
South Sea cultured pearls
Cultured pearls come in a variety of sizes and South Sea cultured pearls are coveted for their large size. - Courtesy Paspaley
Shape: Round is the most difficult shape to culture, making it the rarest cultured pearl shape and—if all other factors are equal—also generally the most valuable. There are exceptions, though. Well-formed pear, oval or baroque (irregularly shaped) cultured pearls are also prized by pearl lovers.

Japanese saltwater cultured pearls Different pearl types are held to different standards when classifying shape. Japanese saltwater cultured pearls are held to the strictest standards for shape. From top to bottom these strands are classified for shape as round, near-round, semi-baroque and baroque.
Colour: Natural and cultured pearls occur in a broad range of hues. There are warm hues like yellow, orange and pink, and cool hues like blue, green and violet. Pearls have a wide range of tone from light to dark. Pearl colours tend to be muted, with a soft, subtle quality.

Japanese saltwater cultured pearls
These Japanese saltwater cultured pearls display the white colour most consumers associate with pearls. - Courtesy Paljoue International Inc.
  Tahitian saltwater cultured pearls
Cultured pearls can come in a variety of amazing colours. These Tahitian saltwater cultured pearls have a colour intensity that’s almost like neon lights. - Courtesy Frank Mastoloni & Sons, Inc.
Pearl colour can have three components. Bodycolour is the pearl’s dominant overall colour. Overtone is one or more translucent colours that lie over a pearl’s bodycolour. And orient is a shimmer of iridescent rainbow colours on or just below a pearl’s surface. All pearls display bodycolour, but only some show overtone, orient or both.

Natural pearls from French Polynesia
These natural pearls from French Polynesia have a dark grey to black bodycolour. The middle pearl shows pink and green orient, while the overtone of the pearl on the left is mostly green.
The law of supply and demand determines the value of certain pearl colours at any given time. If supplies of high-quality pearls displaying a preferred colour are low, their prices can rise to unusually high levels. Other complex factors, like fashion trends and cultural traditions, can influence colour preferences.

Lustre: Of the seven pearl value factors, lustre might be the most important. Lustre is what gives a natural or cultured pearl its unique beauty.

  • Excellent – Reflections appear bright and sharp
  • Very Good – Reflections appear bright and nearly sharp
  • Good – Reflections are bright but not sharp, and slightly hazy around the edges
  • Fair – Reflections are weak and blurred
  • Poor – Reflections are dim and diffused
Within a pearl type, when other value factors are equal, the higher the lustre, the more valuable the pearl.

Japanese saltwater cultured pearls
From top to bottom, these Japanese saltwater cultured pearls show excellent, very good, good, fair, and poor lustre. The differences in the sharpness of the reflections between each adjacent strand are subtle but still noticeable.
Pearl necklace
South Sea saltwater cultured pearls often have a beautiful satiny lustre. - Courtesy King Plutarco, Inc
Surface quality: Like coloured stones, most pearls never achieve perfection. Some might show abrasions that look like a series of scratches on the surface, or a flattened section that doesn’t affect its basic shape, or an irregular ridge that looks like a crease or wrinkle.

If surface characteristics are numerous or severe, they can affect the durability of the pearl and severely depress its value. Surface characteristics have less effect on the pearl’s beauty and value if they are few in number, or if they are minor enough to be hidden by a drill-hole or mounting.

Nacre quality: Lustre and nacre quality are closely related. If the nucleus is visible under the nacre, or if the pearl has a dull, chalky appearance, you can assume that the nacre is thin. This affects the lustre as well as the durability of the pearl.

Multicolored Tahitian Cultured Pearls  
Good nacre quality often results in attractive lustre, like the lustre of these beautiful
multicoloured Tahitian cultured pearls. - Courtesy Armand Ascher Pearls, NY
Matching: Jewellery designers sometimes deliberately mix colours, shapes and sizes for unique effects, but for most pearl strands, earrings or other multiple-pearl jewellery, the pearls should match in all the quality factors.

White South Sea Cultured Pearl Strand  
The white South Sea cultured pearl strand is well matched for all value factors. Even
with its assorted hues, the multicoloured strand is also considered well matched.
- Courtesy Armand Ascher Pearls, NY