Gemstones I Love – Part 5 – Freshwater Pearls

Pearls are unique!   These beautiful creations can be termed organic gems:  pearls are formed inside oysters and mussels when a bit of sand or other irritant gets inside the mollusk’s shell. The mollusk secretes layers of a lustrous material called nacre around the foreign object to protect its soft internal surface.    As layer after layer of nacre covers the irritant, a pearl is formed.

There are a number of different types of freshwater pearls, here are a few – natural pearls happen all on their own; cultured pearls occur when a foreign body or irritant is inserted into the mollusk to start the pearl’s formation; Biwa pearls come from Lake Biwa in Japan; baroque pearls are irregularly shaped freshwater pearls; blister pearls form against the mollusk shell (Mabe pearls are blister pearls that have been intentionally created); Rice pearls (of any size) have the shape of a grain of rice).  Beautiful and lustrous Keshi pearls can be either freshwater or saltwater – these pearls occur when the pearl lacks a nucleus.

Creating a pearl can take several years. Pearls may vary in color from white to those with a hint of color such as peach or pink, to brown or black. The coloration of the pearls formed depends on the type of mollusk and the water where the mollusk lived.

The photos show a freshwater pearl necklace accented with a freshwater and keshi pearl flower as the closure.  The link is

The pearl is the birthstone for June.   coin and stick pearl necklace clasp detail coin and stick pearl necklace clasp_1Because the nacre is an organic substance, pearls can be sensitive to extreme heat, acids, dryness, and humidity.  Pearls measure 2.5 and 4.5 on the Mohs hardness scale so they are quite soft compared to other gems.    The value of pearls depends on their perfection – the most valuable pearls are perfectly symmetrical and are iridescent.

Recently I have been learning about dyeing pearls to fill a custom order.  You can easily find instructions for dyeing pearls online and also color charts and recipes for mixing the dyes.

This was my first experience with trying to dye something like a pearl.   My past experience is in dyeing fabrics.   I used 2 colors of liquid RIT to create my final color, following a recipe from RIT.   I tested the mixture on some freshwater pearls.   I was working to achieve a seafoam color for the finished pearls.

My experiment was a lot of fun!   My first discovery was that the test pearls took the dye differently than those that I wanted to dye for the custom order.    I also observed the one of the colors in the mixture seemed to be absorbed preferentially and it was not the color I needed to get.   In the end, I got my seafoam color, but not without considerable experimentation.