Pearl Luster: the brilliancy and soul of pearls.It displays the pearl's unique beauty and helps people discover this precious water-grown gem gift from the Mother Nature.
Sometimes, people get so involved in examining the shape and blemishes of pearls that they overlook the pearl luster. In other words, they are overlooking the beauty source of a pearl. A chalky pearl might look like nothing more than a plastic bead. The stronger the luster is, the higher the pearl value. Luster is one of the most important factors in determining pearls value for all types.
As a natural attribute, the luster of a pearl depends on the quality of the nacre -- its transparency, smoothness and overall thickness as well as the thickness of each of the microscopic layers of nacre.
Luster is also a light phenomenon depending on the quality and quantity of the reflected light. Therefore when people judge pearl luster, lighting condition must be taken into account. Gemologists and appraisers normally grade pearls under standardized lighting conditions. However, people will encounter various lighting situations when shopping for pearls. The stronger and more direct the light, the more lustrous the pearls will look.
The pearls very gradually change in luster as we went down the lines. There isn't any distinct dividing point in those strands of pearls. That is why the pearl industry has not yet adopted a standardized system for grading pearls until now. The luster grading standard will differ from one dealer to another for the uninformed standard luster reference.
Tips for judging pearl luster
1. Examine the pearls on a flat white surface, e.g. white cloth, paper or tray.
2. Examine the pearls directly under a light instead of away from the light.
3. Look at the light reflections on the pearls and feel how sharp and intense they are.
4. Look for the contrast of the brightest and darkest areas of the pearls; see whether the contrast edge is clear.
5. Compare different pearls under same condition; this comparison will help you have a relative idea of what you want.
GIA pearl description for luster
Excellent reflections are bright, sharp, and distinct
Good Reflections are bright but not sharp, and they are slightly hazy around the edges
Fair Reflections are weak, hazy, and blurred
Poor Reflections are dim and diffused
Pearl Nacre, you may not directly see how the pearl nacre affects the beauty and value of pearls. But it does. A lustrous pearl has more than just a shiny, reflective surface. It also has a glow from within, which coming from pearl's multiple layer of nacre. Furthermore, thicker nacre costs pearl farmer more time to culture and makes the pearl more durable.
The pearl nacre is quite different from Freshwater pearls to saltwater pearls for their different culturing methods. Nearly a whole freshwater is composed of nacre while saltwater pearls are with limited nacre and large nucleus. Therefore, the nacre judgment on freshwater pearls doesn't that matter as on saltwater pearls.
Tips for judging pearl nacre
1.Check pearl luster. If the pearls look dull and chalky, it is most possible that they have thin nacre.
2.The nacre coating that has cracks or peeling indicates thin nacre.
3.Suspend the pearls and let light shine through them. If you can see the stripes or wood grain of the nucleus, the nacre must be very thin.
4.Check nacre thickness from the drill-hole.
GIA pearl description for nacre( for Akoya pearl only)
Very thick: At least 0.5mm on all the pearls of the strand
Thick: At least 0.5mm on most pearls of the strand
Medium: 0.35-0.5 mm on most pearls
Thin: 0.25-0.35mm on most pearls
Very thin: 0.25mm or less on most pearls.