This "Pearls of the Week" is from Dave LeBlanc. Dave is a researcher and owner-operator of Lagoon Island Pearl Farm near Tofino, British Columbia, Canada.
Most natural pearls form from damage to the animal, but some form as a result of illness. Dave postulates that epithelial cells that grow shell nacre may be prolapsed into the inner tissue forming nacre pockets in the body.
This "California mussel" (Mytilus californianus), displays masses of pearls due to autoimmunity from antinuclear antibodies.
"There are pearls as small as 10 microns.", explains Dave.
"These pearls are the result of auto-immunity. Most natural pearls formed by parasites, perforations and shell damage are "periostracial" in origin. Including aqua cultural grafts. That means, the mollusk creates a water tight barrier before mineral layers are formed.
These pearls are myostracial in origin. There is no water to block because they're formed deep within the tissues. They are an immunological response. Blood cells (similar to T-strain mycoplasma in mammals) are implicated attacking otherwise healthy tissue, hence subsequently becoming inflamed. In almost every case it's the indirect result of bacterial infection. While most mussels having these infections show no adverse effects, a small percentage will develop auto-immune disease, but live otherwise full life terms.
Mussels don't have gonads like other pearl oysters, instead having a complex series of gonoducts which share the same space as the mantle skirts. The tissues of reproductive organs are almost always the site of onset. The mussels will always test positive for anti-nuclear factors. As such, when the pearls are examined by candling or microscopy, they'll present with no visible nuclei in the views."
Photos by Dave LeBlanc
Read more about Lagoon Island Pearl Farm by visiting the website: