A pearl nucleus is manufactured from freshwater mussel shell which has been worked into a perfect sphere and polished.
The Nucleus Is An Imperative Part Of Perliculture
The nucleus of a pearl, although it is not typically visible in a harvested pearl, is extremely important in the culturing process. The nucleus is the seed that impregnates the oyster and produces the gem ? the pearl. Without a quality nucleus it is impossible to create a quality pearl.
Most Pearl Nuclei Are Made From Shells Collected From The Mississippi River Basin
The bead material used to create the nucleus has historically been derived from freshwater mussel shells found mostly in the Tennessee River, in the Mississippi River Basin. As available stock of natural shell has dropped significantly as the popularity of cultured pearls has risen, other sources of shell have been explored. Chinese freshwater shell is now used to a large extent, as is the illegal use of Giant Clam shell (Tridacna gigas). Giant Clam is protected by the CITES treaty.
The Shell Is Primarily Worked In Asia
The shell harvested from these rivers is typically first transported to Asia to be worked. This process involves cutting the thick portion of the shells near the hinges into strips then into cubes. These cubes are then shaped in to perfect spheres by first edging by hand, then grinding with plates, tumbling in an acid solution, and polishing. Throughout the process beads are carefully inspected to ensure a perfect shape. These finished nuclei are then separated by size and quality.
The Finished Nuclei Are Graded Then Sold
The finished product falls into different quality ranges in a similar fashion as pearls themselves. There are three qualities commonly sold on the market today. Akoya pearl production demands the highest grade bead due to nacre depth.
The top-grade bead is one that is perfectly white. A slightly lower-grade bead with have some slight discoloration, and a low-grade bead with have dark bands of calcium carbonate buildup appearing as rings around the nucleus. This banding is referred to as striation. These low-grade nuclei are commonly used in the production of darker cultured pearls such as Tahitian pearls. Any visible banding on the nucleus, even if the pearl is medium grade and the banding is light, can be detected in a light-color, medium to thin nacre pearl by the presence of blinking when examining and rotating the pearl.
Visiting a Pearl Nucleus Factory with Pearl Paradise
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