Assessment criteria

Classifying the beauty

As far as pearls are concerned, quality is synonymous with beauty.

The South Sea pearl is the undisputed queen of the pearl kingdom for quality and size.

There are five fundamental criteria for assessing pearls. These are: 

Lustre – This is a measure of the intensity and beauty of light reflected by a pearl's surface. A thicker and more uniform layer of nacre accounts for a more luminous pearl.

Excellent - Good - Fair - Poor

Surface Purity – As pearls are natural gems they sometimes exhibit imperfections and defects. Such imperfections are natural characteristics of a pearl and so they do not detract from their original beauty. 

No visible blemishes - Small blemishes - Widespread blemishes - Noticeable blemishes

Shape – The shape of a pearl depends on the thickness and the process of formation of the nacre layers. South Sea pearls can have an infinity of possible shapes.  
Round - Oval - Drop - Button - Near Round - Baroque - Semi Baroque - Ringed

Colour – Refracting light through the calcium carbonate crystals of the nacre layers, pearls can display practically all the colours of the rainbow.
White - Rose White - Cream – Gold - Light Grey. Pearls with green, peach, cognac or champagne hues are rarer.

Size – South Sea pearls are the largest pearls in the world. In general they are between 10 to 15 millimetres in diameter but pearls with a diameter between 15 and 20 millimetres have also been found.