Proper Expression Of Pearls' Size

As every body knows that the larger the size, the higher the price of a pearl. But pearl's price jumps between pearl sizes are often uneven. When the size reach the 8 - 9mm or above, pearl prices tend to increase much higher.

According to CIBJO, the world Jewelry Confederation, different pearls are measured by different methods with different minimum units' expression.Here is the general pearl size measuring methods:





Pearl Size Description

Single PearlRound shape: average diameter

Fancy shape: maximum diameter, maximum lengthPearl

size: <10mm, expressed to the nearest 0.25mm

>,=10mm, expressed to the nearest 0.1mm

Graduated Strands: Maximum diameter of the largest pearl and the smallest pearl on the strand

Pearl size:expressed to the nearest 0.1mme.g.8.6-13.3mm

Uniform strand: Stated as the minimum size

Pearl size:expressed to one half(0.5)mm variations

e.g. 7.0-7.5mm

How to measure the pearl size?

1. Different types of pearls have different expected size ranges. A guide: akoyas typically range from 4-8mm, Tahitians from 8-14mm, South Sea pearls from 9-15mm, and freshwater pearls from 5-11mm. All have different expected size ranges, and anything outside the range will be reflected in the price. If the pearl size reach or over the rang, the price will be more higher. Akoyas over 8.5mm, Tahitians over 15mm, South Sea pearls over 17mm, and freshwater pearls over 12mm. 2. Different diameter class by diameter length Mini pearl: diameter <> 8mm 3. How to measure the pearl size? Usually we use the electronic digital caliper to measure the pearl size. It could measure the diameter of loose pearl and the length of pearl jewelry accurately. Except the error by temperature changing, chemical reagent contact, and moisture. The results of measurement are very accurately.