Pearl

Pearls were not mined, they were the product of oysters or other mollusks, but they were treated like gemstones.

Description
Pearls were formed of layers of tchazar (aragonite) around a bit of grit or other irritant, growing inside a mollusk over the span of a few years. This slow process gave pearls a smooth surface with a deep, rich luster. Pearls were predominantly white but did occur in other colors such as gold, pink, or silver; rainbow and black being the most rare and valuable.

Over-sized pearls (3 in or 8 cm in diameter or more) were frequently flawed in some way and not as valuable. One exception to this was a perfect head-sized pearl that was enchanted to become a crystal ball. A typical pearl has a base value of 100 gp to 500 gp, depending on market value.

Powers
Pearls were used as a material component in many spells, particularly those that reduced acids to plain water, and neutralize poison. Crushed to a powder, pearls were used in creating all types of magic mirrors. Well-known magical items included the pearl of power, the pearl of the sirines and the pearl of wisdom.