When it comes to pearls, many people mention characteristics such as their origin from mussel shells, the distinction between saltwater and freshwater pearls, and their popularity as a family favorite.

However, do you know the difference between nucleated and non-nucleated pearls? Pearls come in various shapes, with round and pear-shaped being the most typical.

These pearls display a range of colors, typically white or light-colored, and varying degrees of luster, making them suitable for both decoration and medicinal purposes.

Nucleated pearls and non-nucleated pearls differ in their formation processes.

Non-nucleated pearls are created through the artificial implantation of a cell membrane from a mussel, leading to the development of a pearl layer from the inside to the outside. This intricate process typically spans 4-5 years, and a single mussel shell has the capacity to produce multiple pearls. It's worth noting that, in general, most non-nucleated pearls are freshwater pearls.

On the other hand, nucleated pearls are typically saltwater pearls, although some freshwater pearls can also be nucleated.

Formed by the natural secretion of nacre by marine shellfish, these pearls wrap around an artificially implanted nucleus with a growth period of 2-3 years. Usually, a mussel shell produces only one pearl.

High-quality saltwater pearls are mostly formed by a round artificial pearl nucleus, enveloped by the natural secretion of mother mussel nacre.

The shape of saltwater pearls is mainly determined by the planted nucleus, with round and semi-circular shapes.

Truly natural round saltwater pearls without nuclei are rare and expensive.

Another situation with nucleated pearls occurs when a clam's coat membrane is stimulated by foreign objects (sand, microorganisms, etc.).

This stimulation prompts epidermal cells to form a pearl capsule around the foreign body, leading to the creation of "nucleated pearls."

Distinguishing between nucleated and non-nucleated pearls involves several factors:

1. Luster: Saltwater pearls generally have a better luster due to the higher density of nacre than freshwater pearls, providing a strong mirror-like effect.

2. Pearl Layer Thickness: Non-nucleated pearls are composed of 100% nacre, resulting in a thicker pearl layer compared to nucleated pearls. International regulations require a nacreous thickness of at least 0.3mm for saltwater pearls to be sold.

3. Shape: Non-nucleated freshwater pearls lack external support for shaping, making it challenging to form perfect circles. In contrast, nucleated pearls typically have a more refined round shape.

4. Size: Non-nucleated pearls grow naturally in mother-of-pearl, leading to varied particle sizes.

In the case of nucleated pearls, freshwater pearls range from 1mm to 18mm, while saltwater pearls are generally between 6mm and 18mm.

5. Color: Freshwater pearls come in almost all colors, including many rare shades.

In contrast, saltwater pearls, especially Tahitian pearls, boast unique colors.