r
sdsadadsadadadasdsadadadadcssdsadsadas Your best pearl knowledge guide.
    Pearl Treatments
    Pearl History
    Pearl Farming
Pearl Price factors
copyright 2006 AllAboutPearl,about pearl knowledge.All right reserved.
Sponsored link

 

Previous    Next
This phenomenon is called "blinking" and can sometimes be seen in thinly coated pearls. When rotated, each of these pearls "blinks." Pearls with thick nacre should not blink.

A more accurate way of judging nacre thickness is by examining the drill holes of the pearls, preferably with a 10-power magnifier such as a jeweler's hand loupe. (If
you are seriously interested in gems, you should own a fully-corrected, 10-power, triplet loupe. You can buy them at jewelry supply stores. Plan on paying at least $25 for a good loupe).

Examining drill holes with a loupe will also help you detect dyes and imitations. The drill-hole method is too slow to be practical for dealers, but it is a good way for less-skilled people to estimate nacre thickness. It also allows appraisers to give a more objective measure of nacre thickness.

If you have some pearls at home, try examining their drill holes with a loupe under a good light. Find the dividing line between the nacre and the bead. Then look at a millimeter ruler with the loupe to get a visual image of a 0.35-mm thickness. Compare this thickness to that of the nacre. Seeing actual examples of thin, medium and thick nacres is an easier way to learn to tell the difference. This book suggests 0.35 mm as a minimum nacre thickness because it has been mentioned in the trade as a minimum. For example, Hiroshi Komatsu of the Tokyo Mikimoto research lab is quoted as saying, "Our tests show the best luster and color occur with at least 0.35 mm of nacre, and Mikimoto pearls are always thicker" (as quoted by Fred Ward in the August 1985 issue of National Geographic). Keep in mind that the nacre thickness may not be the same throughout a pearl. Nacre measurements can also vary depending on the measuring instrument used and the person doing the measuring. So consider the 0.35-mm minimum as an approximate thickness.

When you have your pearls appraised, ask if nacre thickness is indicated on the report. Also ask how the appraiser's nacre-thickness categories are defined in terms of millimeter thickness. A term such as "thin" can vary from one person to another, so definitions are necessary. There must be a drill hole or other opening on a pearl for an accurate estimate of nacre thickness to be made visually.

Also make sure that the millimeter thickness is of the radius of the pearl, not of the diameter, which would be twice the nacre thickness along the radius. If someone tells you the average nacre thickness of an Akoya pearl is 1 mm, figure they have doubled it. Today it's hard to find Akoya pearls with even a 0.4-mm thickness.

It's not deceptive to sell thin-nacre pearls as long as the thin nacre and its consequences are disclosed to buyers. Ideally, consumers could choose from a wide range of nacre thicknesses and know exactly what they were getting for their money. Since this ideal does not currently exist, it's to your advantage to pay attention to nacre thickness and to learn to detect thin nacre yourself.

Is Nacre Thickness Important

As you shop, you may encounter pearl salespeople who claim nacre thickness is unimportant and has no effect upon price. Beware. All their pearls may be of low quality. Ask them, "Why is something which affects the beauty and durability of my pearls unimportant?"

As for price, it has to be affected by nacre thickness. It naturally will cost a farmer progressively more to culture pearls for 6 months, 1 year and 1 1/2 years. The additional cost must be passed on to the buyers.
- sale7 - cheaps2