Pearls are the most valuable of all organic gemstones. Prized for 6000 years. Pearls chemical makeup varies by region & environmental factors but the basic formula is irritant is coated (mother of pearl)^
"At millimetres in diameter, this is the world's largest fine-quality round pearl. It was grown on the Cygnet Bay Pearl Farm north of Broome in Western Australia, and has spent the last few years being showcased around the world.