Being one of the most trending gemstones of 2019, pearls both natural and cultured come in a large variety of colours. Although the most familiar pearl colours are white, cream and black, this beautiful gemstone’s colour palette extends to many different hues.
Pearl Origin and Formation
Pearls are organic gemstones that are formed by shelled molluscs such as mussels and bivalved oysters. They build up around a microscopic irritant and are made up of mother-of-pearl (nacre) which consists of calcium carbonate and complex proteins that form mollusc shells.
The name “pearl” comes from the Middle English word “perle” meaning “leg”, thought to be due to the ham-leg shape of bivalve molluscs.
The uniqueness of these gemstones is that they can be plucked from the shell naturally beautiful. They come fully formed with no need to be cut or polished.
The appearance of natural and cultured pearls is the same, however, natural ones are much denser. The only way to distinguish between natural and cultured pearls is to examine their internal structure. To do this, experts use endoscopes and check the internal layers. Natural pearls should have concentric ones.
Before pearls were cultured by man, they were harvested from the waters of the Persian Gulf, Shri Lanka, China, and Europe. Later pearls were discovered in South America as well.
In the early 20th century when the natural pearls were almost depleted, people began to culture pearls first in China and Japan, then all around the world.
Nowadays, natural sea pearls can be found in Japan, Central and South America, Australia, Madagascar, Burma, the Philippines, the Persian Gulf, the Gulf of Manaar, while river pearls are found in Asia, Europe and North America.
Cultured pearls come from Indonesia, the Philippines, Australia, China, Japan, French Polynesia, and the South Pacific Islands.
Pearl Colour and Luster
Pearls come in a variety of colours, such as white, cream, pink, silver, golden, blue, green and black. Some pearls also show iridescence which is known as orient.
Pearls are often bleached to enhance or lighten their colour. This treatment is used to achieve a uniform colour for a single piece of jewellery.
The lustre depends on the quality of the nacre. High-quality pearls have a pearly lustre and exhibit sharp and bright reflections. They also have a smooth and blemish-free surface.
Pearl Cut/Shape and Size
As mentioned above pearls come fully formed with no need to be cut and polished. They can be round, oval, pear-shaped or misshapen (baroque). However, the best pearls are regularly shaped ones.
The most valuable pearls are those that have a perfectly symmetrical sphere or drop shapes.
Pearl sizes depend on the type of molluscs they are formed in. Typically their size ranges from 2 mm to 16 mm in diameter.