Pearls are organic gemstones formed when a mollusk (primarily oysters and mussels) secretes layers of nacre around an irritant within its mantle. Their internal texture consists of alternating layers of tiny aragonite (calcium carbonate) crystals and organic binder, giving pearls their unique orient or pearlescent luster. The luster of a pearl is its most important quality characteristic, produced by the combined reflection, refraction, and diffraction of light by the nacre layers. Pearls are generally untreated, though some may undergo slight bleaching or polishing to enhance their appearance.
Pearls are not crystals in mineralogy but rather composites of calcium carbonate (aragonite or calcite) and organic matter. Their Mohs hardness is 2.5-4.5, making them relatively soft. Pearls are considered the "tears of the sea" and the "gem of the moon," symbolizing purity, wisdom, wealth, and serenity. They are believed to balance emotions, bring calmness, and enhance the wearer's intuition and feminine energy.
Freshwater Round Pearls: Primarily sourced from freshwater mussels, they typically have a thicker nacre, resulting in a softer luster and a wide range of colors, including white, pink, and purple. Shapes vary from near-round to oval, with high-quality round pearls boasting luster comparable to saltwater pearls.
Freshwater Baroque Pearls: Refer to irregularly shaped freshwater pearls. These pearls are highly valued for their unique, asymmetrical forms, with each one being distinct and typically possessing good luster.
Seawater Round Pearls: Primarily sourced from saltwater oysters, such as Akoya, South Sea, and Tahitian pearls. They generally exhibit a stronger, mirror-like luster and a more perfect round shape, with a relatively thinner nacre.
Seawater Baroque Pearls: Refer to irregularly shaped saltwater pearls. Similar to freshwater baroque pearls, they hold artistic value due to their unique shapes and often stronger luster.