The "classic" piece of pearl jewelry is a string of pearls or the pearl necklace. Akoya pearls are the traditional type of pearl used in necklaces, but freshwater pearls, Tahitian black pearls and South Sea pearls are also used. Akoyas are the traditional white or cream color pearls. Tahitians and South Sea pearls produce necklaces of darker tones. Freshwater pearls can be either white or dark, and are generally more affordable than saltwater pearls.

The pearls used in a string of pearls can all be of the same size or they can be graduated with larger pearls in the center and successively smaller pearls running back on each side to the clasp. Whichever style you choose is a matter of personal taste. However, good matching of the pearls in the strand is of paramount importance. Graduated pearls require careful sizing. If the strand is not carefully matched, it will distract from the appearance and its value. You should also make sure that the pearls are all center-drilled. Pearls that are drilled off-center will never lie properly and will greatly lower the value.

Traditionally, certain pearl sizes are considered appropriate for women of various ages. The size of the pearl in a string of pearls is an indicator of the wearer’s social position and wealth. Smaller pearls (5.5-6.5 millimeters) are generally appropriate for teenage girls and younger women up to about age 20. Women in the range of the mid-20s to mid-30s traditionally wear a string of pearls with pearls 6.5-8.0 millimeters. This size is not too showy.

Pearls in a string of pearls 8.0-9.0 millimeters in size are indicators of status, class, and success. Women in their mid-30s to mid-40s traditionally wear them. These pearls tend to be more expensive. Pearls 9.0-10.0 millimeters are both rare and expensive. Wealthy, matured women generally wear them.

A string of pearls typically come in the following categories: collar (12-13 inches), choker (14-16-inches), princess (17-19 inches), matinee (20-24 inches) opera (26-36 inches) and Rope (40 inches and over). The make of the necklace can have a significant impact on its appearance and value.

The precision that goes into the matching of the pearls is called the make. Before you purchase a string of pearls, you should always check to see how well matched the strand.