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luster and iridescence come from high quality nacre and any pearl with these characteristics has quality, thick nacre. When judging nacre look for uniform iridescence, intensity of luster, cracks and peeling, estimate thickness near the drill hole between the nacre and the shell bead (nacre is lighter). Pearls are very thick with at least .5 mm on all pearls, thick with at least.5mm on most pearls, medium with between .35 and .5 mm on most pearls, and thin with .25 mm or less on most pearls. Luster is also important and one of the first factors to notice. Luster is an intense brightness that illuminates from within the pearl rather than just being shiny?like in imitation pearls. The intense brightness results from light being reflected throughout the numerous layers of nacre. Quality pearls will have a sharp contrast between the brightest area where direct light is hitting the pearls and the shaded area creating an illusion of a ball within the pearl.? Check for luster by examining them under a fluorescent lamp and rolling them from side to side to examine uniform luster. Examine pearls over a light gray or white material and never black because it is harder to see the true quality of the pearl. Pearl color is also important. When choosing pearls note there body color and overtones. The most desirable and more rare white pearls have rose?colored overtones. Cream colored pearls are more affordable because they are less rare. Als 上一页 [1] [2] [3] [4] 下一页 |
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