I made a study tutorial for my GIA Colored Stones exam, and I’d assumed I might share it with you. This is the compilation of my readings, the interactive films, also as my full-day in Atlanta mastering the best way to grade pearls. The photographs are iphone photographs from my get the job done station along with the hue wheel that is made use of at GIA to grade pearls. The above mentioned photograph is my mabe pearl-this is what it seems to be like just before they reduce it out and assemble a mabe pearls.
Normal pearl development commences whenever a foreign object gets inside a pearl-bearing mollusk’s shell and irritates its tender tissue. The mollusk attempts to lessen the results on the irritant by coating it with layers of nacre.
Purely natural pearl sources: Persian Gulf, waters of Ceylon, Chinese rivers and lakes, rivers of Europe
The decrease of organic pearls began because of to three aspects:
Mikimoto’s creation of culturing pearls through the twenties
The creation of plastic, especially plastic buttons.
The discovery of oil within the Persian Gulf-became the area’s new aim alternatively than pearls, at the same time as polluting the pearl beds.
The trendy cultured pearl system began close to 1890. Mikimoto turned the forerunner on the bunch together with his worldwide marketing marketing campaign during the nineteen silver earrings for mentwenties. For the duration of Globe War II, the culturing pearl marketplace shut down-it was right until the late nineteen forties when items revived, and lots of American soldiers brought property cultured pearl necklaces property for their sweethearts from Japan.
South Sea cultured pearls > Western Australia > 1950s
Tahitian cultured pearls > French Polynesia > 1960s
Chinese freshwater cultured pearls > 1970s
Saltwater cultured whole pearl grows from a mantle tissue piece and a bead nucleus that may be inserted into the host mollusk’s gonad.
Akoya–old Japanese term for “oyster.” Akoyas are found within the saltwaters of Japan, China and Vietnam within the Pinctada Fucata oyster. Typically 2-10mm, white with a rose overtone, and excellent luster. Usually white, cream or silver in hue-there are no black akoya pearls (if so, they are dyed). Japan experienced some bad water pollution issues and millions of oysters died because of it through the 1990s. silver ringsJapan is still trying to recover from such a loss in their pearl industry.
2. South Sea-found within the saltwaters of Australia, Indonesia and the Philippines inside the Pinctada Maxima oyster-either silver-lipped or gold-lipped oysters (each account for the color of pearl it produces). Typically 8-24mm with a gentle, satiny luster.
3.Tahitian-found from the saltwaters of French Polynesia plus the Cook Islands from the Pinctada Margaritifera oyster-which is black-lipped. Typically 8-17mm with gray, dark gray, black, bluish- green, greenish-blue colors with trade names like Aubergine, Peacock and Pistachio.
Freshwater cultured whole pearls grow from mantle tissue pieces implanted into the host mollusk’s mantle.
Chinese Freshwater-found in the riverbeds and lakes of China (also Japan and US) in a mussel. Typically 2-13mm with about 1500 tons of production, and only 2% being spherical. Takes about 2-6 years to harvest, in which one mollusk can produce up to 40 pearls at one time.
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Seven Value Aspects:
1.Size: bigger is better.
2.Shape: *can have circled pearls also, like “circled drop” “circled oval”
Spherical- round or near-round
Symmetrical- oval, button or drop
Baroque- semi-baroque or baroque
3.Color: the pearl hue circle comes into play here. There are a few other characteristics, like:
Bodycolor, Overtone (if present), Orient (if present)
Neutrals-white, black and gray
Near-neutrals-cream, silver, brown
Hues-all other (fancy) colors >> Hue wheel
4.Luster: South Seas rarely have intense luster-more satiny luster. Tahitian and freshwater pearls can have an almost metallic luster. Coldwater= higher luster
Excellent-bright and sharp
Very good-bright and near sharp
Good-bright and not sharp
Fair-weak and blurred
Poor-dim and diffused
Clean, lightly spotted, moderately spotted, or heavily spotted
Look for characteristics like: abrasions, scratches, bumps, chips, cracks, flats, gaps (areas where nacre doesn’t cover), pits, spots and wrinkles
6. Nacre quality: Looking for nacre thickness, its translucence and uniformity.
7. Matching: may be not applicable to jewelry that features only one pearl.
Excellent- uniform appearance
Very Good- very minor variations
Good- minor variations
Fair- noticeable variations
Poor-very noticeable variations
If you still would like more information, this is my favorite book on pearls: