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