People have been decorating themselves for millenia. Ancient shells with red ocher residue has been found in South Africa dating to nearly 100,000 years. Ancient shells with symmetrical holes drilled in them were found in a nearby cave, suggest these people made necklaces.
Pearls have long been coveted by those that can afford them. Cultivation has allowed those of more modest means to purchase them as well.
As with diamonds and other gem stones, pearls vary quality due to differences in shape, color, and texture. Of the 8,000 or so species of oysters, only about 20 of those are able to constantly produce pearls. For the most part the pearls these oysters do produce, few maintain a round or spherical shape.
The size of the pearl will also impact the pearls value. Size refers to the diameter of the pearl in millimeters.
Size also goes hand in hand with the shape of the pearl. The ideal shape is supposed to be perfectly round. However, using irregular shapes can reduce the price of the pearl and in some cases improve the uniqueness of the jewelry. Most of the common shapes are oval, tear dropped or look button like.
Other factors in the price of a pearl are color, lustre and its surface. Ideally the perfect pearl would be silvery white, very reflective and contain no surface blemishes. Although color is a personal preference and pearls come in a variety of colors both naturally and syntactically.
In the end though, what really matters is how the individual feels about the particular piece of jewelry. If the pearls are to be enjoyed instead of an investment piece, than none of the grading rules jewelers use really matter. What does matter though, is that the color and size of the pearls perfectly complement the owners beauty and grace.