Valuation of Pearl
The value of pearls is determined according to the shape, colour, size, surface condition and luster.
Shape
The shape is one of the most important elements for pearl. The most desirable pearl is spherical in shape or round, however, a large and round natural pearl are very rare and is highly valued. Good-quality pearls can also be found in other shapes at lower price compared to a perfectly round shaped pearl.
Surface condition
The surface condition and the luster of pearl are inter-related. The surface condition refers to the smoothness and cleanness of the pearl. Discoloration and blemishes on pearl surface are also taken into account when evaluating surface condition. The luster of pearl measures the brilliance and the reflection of light. A good-quality pearl usually have a smooth and clean surface, and high in luster, which means it shines and shimmer under the light. Sea pearls usually have a higher luster than freshwater pearls.
Colour
Pearls come in a wide variety of colour; in general, the body colour and overall tone are to be considered. Body colour refers to the overall colour of pearl and overall tone refers to the translucent colour appears on the overall body. When evaluate the colour of pearl, it varies based on individual’s preference.
Size
The size of pearl is measured by its diameter in millimeter. Pearls can be smaller than one millimeter, referred as “seed” pearl, or as large as 20 mm. When all the other factors are equal, the larger the pearl, the more valuable it is. Most pearls in the market are 6.5 mm to 7.5 mm in size. Traditionally, natural pearls are priced based on the weight and cultured pearls are priced based on the size. Natural pearls are weighed in grains (1 grain 0.05 g = 0.24 ct or 1/4 carat).