Quality Factors

A pearl may be judged by seven factors. Luster is perhaps the most important indicator in evaluating cultured pearl quality. Other important factors include nacre thickness, surface, shape, size, color, and weight. As a general rule, the overall balance is more important than any single attribute, and it may be helpful to keep this in mind as you read on.

Luster
Luster can be considered the radiance or glow of a pearl and is determined by the quality of the nacre coating. Thicker nacre increases the quality and durability of a pearl as well as its luster, but thicker nacre requires a long cultivation period. High luster pearls reflect objects almost like a mirror with high contrast between the light and dark areas. If the luster is good, your reflection will be visible in the pearl's surface. The clearer the reflection is, the higher the quality of the luster. Low luster pearls have poor reflective qualities and appear dull or chalky. Dahlia only carries pearls of medium to excellent luster. Pearls with high luster account for only 8% to 10% of all cultured pearl production in any given year, so these lustrous pearls usually command premium prices. With all other factors such as surface, shape, color and size being the same, a medium luster 7mm pearl will cost about 30% more than a low luster pearl of the same size. A pearl with high luster will often be priced about 60 - 70% higher than a cultured pearl with low luster.

Nacre Thickness
Nacre (nay-ker) is the crystalline substance secreted by a mollusk to form a pearl. Thicker nacre translates into a more durable pearl. Natural pearls are all nacre, whereas most cultured pearls have a bead nucleus in the center. Due to rising production costs, there is a tendency to harvest pearls before a sufficient nacre coating has developed. For example, an Akoya 7mm pearl has an average coating only 0.4mm thick (11.4% of the diameter), and an Australian South Sea 15mm pearl has about 4mm nacre (53.3%) coating. Dahlia pearls, like natural pearls, are PURE nacre, due to a special nucleation process. Our pearls take 2.5 - 5 years to cultivate to reach 5 ?10mm. Akoya pearls typically grow for 6 months to 2 years before harvest.

Surface
The surface of a pearl may range from clean to very blemished. The visibility of surface imperfections may decrease the value of a pearl by 30 - 70%. Clean pearls have virtually no flaws, and these pearls are the most valuable and rare. Blemished pearls may contain bumps, abrasions, and spots. Inferior pearls may contain damaging blemishes. Damaging blemishes such as "cracks" and "chips," often near a pearl's drill holes, are blemishes that may become larger.

Shape
The most common cultured pearl shapes are round, nearly-round, off-round, drop, oval, button, and baroque. Baroques are an infinite variety of shapes. The closer a pearl is to a perfectly round or drop shape, the greater its value. Round pearls represent only 3% of the entire harvest, near round pearls about 5%, and oval pearls approximately 15%. Dahlia only uses the top 20% of the harvest. The remaining pearls not suitable for fine jewelry are sold for scrap - ingredients in wine, medicine, and cosmetics.

Size
The diameter of a pearl is measured in millimeters (mm). Dahlia cultured pearls range in size from 2-18 mm while natural pearls range from 0.5-2 mm. Typically, all other factors being equal, a larger cultured pearl is worth more than a smaller one. In fact, the value of a cultured pearl may double for every 0.5mm diameter increase.

Color
Dahlia pearls, cultivated in freshwater, develop into a wider range of colors than any other type of pearls. Colors include a range of light and intense deep colors such as white, pink, peach, tangerine, lavender, plum, cocoa, and more. Dyed colors include an infinite variety of shades. The natural pearl color is determined by the type of mollusk, elements present in the water in which the mollusks grow, and pigments in the conchiolin layers of the pearl. Nacre makes up 82-86% of any pearl, and approximately 10-14% is conchiolin. The remaining 2-4% is water.

Weight
The weight of a single pearl is usually expressed in grains or carats. A grain, the equivalent of 50 milligrams, is usually applied to natural pearls. A carat, the equivalent of 200 milligrams or 4 grains, is the same unit of weight used for diamonds or other gemstones. In Japan, strands of pearls may be sold based on weight measurements called momme ( moh-may ). One momme equals 3.75 grams or 18.75 carats.