Pearl Sizes and Comparisons

Pearls range from tiny 1mm seed pearls to 20mm South Sea giants (mortgage your house if you want a strand of these). For round pearls, the most common size is 7-7.5mm.

Pearl prices rise sharply after about 7mm. The longer they remain in the water the more chance there is of the mollusc dying of disease or other causes, or of the pearl losing it's shape and developing unsightly blemishes.

   Pearl Guide
pearl history a brief history of pearls
how pearls are formed how pearls are formed
pearl qualities and grades pearl qualities and grades
pearl shapes and colours pearl shapes and colours
pearl sizes pearl sizes and comparisons
choosing and caring for pearls choosing and caring for pearls
buying pearls buying pearls - tricks and traps
Measuring Pearls

Pearls are usually measured in millimetres through their round diameter - perpendicular to the axis of the drill hole.

pearls are measured through their round diameter

For example, this 9mm oval pearl is measured along the line of the arrow, not it's length.

Pearl Sizes

Comparing 6mm, 7mm, 8mm, 9mm and 10mm pearls with a British fivepenny piece. The coin measures 18.0mm across.

pearl sizes
6mm 7mm 8mm 9mm and 10mm pearls    


Pearl sizes are often given in measurements like 5mm-5.5mm or 8mm-9mm. This means that the pearls on the strand should fall within these measurements.

Although a half millimetre sounds tiny, the human eye is very good at picking out small differences.
Oval Pearls

oval pearl sizes

 

From the top...

6.0 - 6.5mm
6.5 - 7.0mm
7.0 - 7.5mm
7.5 - 8.0mm
8.0 - 8.5mm

Round Pearls

round pearl sizes

 

From the top...

4.0 - 5.0mm
6.0 - 7.0mm
7.0 - 8.0mm
8.0 - 9.0mm
9.0 - 10.0mm

The World's Largest Pearls

the world's biggest pearls The Pearl of Allah, is the largest known pearl measuring 9.45 inches in diameter and weighing 6.4 kilograms (14.1 lb). The 2006 appraisal value was US$61,850,000. The pearl was taken from a giant clam off the coast of Palawan in May 1934 by a Filipino diver.

Probably the most famous pearl is the 'Hope Pearl' named after it's owner Henry Hope and displayed in the Natural History Museum in London. The pearl was found early in the 19th Century and weighs about 90 grams.

More recently, a silver coloured pearl (shown right) weighing a whopping 170 grams was found on the seabed off an island of Myanmar (Burma).

It's understood that the fisherman who found the pearl donated it to the military government, thus avoiding the unpleasantness associated with an involuntary donation.
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