Luster is the amount of light reflected from the pearl's surface. Luster is the surface glow, as well as the deep mirror-like reflection of the light, or "inner light". Nacre quality in cultured pearls will improve the overall luster. Many even layers of nacre are required to create a highly defined spectrum of color. Only the highest quality pearls with the best luster carry the Paragon Pearls name.
As a product of nature, tiny marks found on pearls are part of their natural texture and are proof of the genuineness of a cultured pearl. These blemishes are produced by outside sea particles and objects that find their way into the oyster and brush against the pearl. A pearl is considered more valuable when the surface imperfections are minimal.
There is a wide spectrum of colors that can be found in pearls. Basic colors include cream, gray, green, blue and pink. The most popular colors are white and pink rosé because these shades flatter the widest range of skin tones. Color is based on preference, but it is always important to find a color that is rich and evenly distributed on the pearl.
Although many shapes are available, perfectly round pearls are the rarest and most valuable. Button pearls are round on one side and flat on the opposite end. Other shapes like tear drop and baroque are also favored because of their uniqueness. They are formed when an outside entity attaches itself onto the forming pearl and it is covered by nacre layers.
Generally, the size of the pearl affects the price. Large pearls are more difficult to cultivate because of the large size of the implanted nucleus. There is an increased likelihood that the oyster will reject the nucleus. Pearls are measured in diameter increments of millimeters (mm). The classic Akoya pearl generally ranges from 3.5mm to 10mm in size. South Sea (White, Golden, or Black) pearl sizes begin at 10mm and can be as large as 18mm.