39.6 CTS SHELL CARVED FLOWER BEAD 11434

2064

存貨單位
尺寸（毫米）: x x mm
重量 (cts)
Certified Gemstones: 不
類型: Bead
顏色

DESCRIPTION:
Gem Type:NATURAL SHELL	Weight (CARATS):39.6 CTS
Color:IVORY TINT	SIZE (mm): 30 X 3 MM
Additional Comments: PIECES- 1 STRAND/ AS IN PHOTO THIS GEM STONE IS NOW IN AUSTRALIA AND WILL BE SHIPPED FROM THERE SO PLEASE BE PATIENT FOR YOUR DELIVERY ARTIFICIAL BLACK DYEING WITH SILVER SALT: Treatment with silver nitrate solutions (AgNO3) is applied since the nineteen thirties to Japanese Akoya cultured pearls. The method was used at the end of the 19th century in the mother-of-pearl industry and natural pearls were also dyed this way. The pearls are immersed for a period of several days or weeks to several months in diluted silver nitrate solution (the dilution ratio is 3 to 4 per cent) and are kept in a dark room. After this, they are exposed to a strong light source (either sun light or artificial light) or they are treated with hydrogen sulphate. Both methods lead to the deposition of metallic silver in an extremely fine distribution in the pearl, causing the dark color. The method enables the production of lighter or darker hues, depending on the quantity of silver produced. An immersion period of several months is required in order to produce truly black colors while shorter periods lead to more brownish or grayish hues. This means that the nucleus remains white, while the outer pearly layer takes on the dark color. The deposition of silver seems to concentrate in the conchioline layer which is often present between the nucleus and the pearly layer. The distribution of silver gets less towards the surface of the pearl. In the case of undrilled pearls diffusion of silver oxide starts however from the surface while in the case of drilled pearls the silver solution will more directly find its way to the border area between nucleus and outer pearly layer. Other Coloration Chinese freshwater cultured pearls in striking artificial colors have been seen on the market since the nineteen eighties. In addition to yellow, there are red, pink, orange brown blue green purple and lilac although rice crispies, baroques and flats were used mainly in the beginning; there have been more rounded shapes also over recent years. Intensely blue, green, yellow, pink, red and purple nearly round pearls, no doubt dyed with chemical agents, have been seen at international trade shows since the late nineteen nineties. No detailed information is available as to the methods used. The colors seem to be permanent and needless to say fall into the lowest price range 7 Pearl Value Factors: * Size: Pearl size is measured in millimeters. Typically, all other factors being equal, a larger pearl of a certain type is more expensive than a smaller one. * Shape: There are three main categories to pearl shape: spherical, symmetrical, and baroque. An example of a symmetrical pearl is an oval, while baroque pearls are irregular in shape. * Color: With cultured pearls, look at body color and, if present, overtone. Bodycolor is the dominant color of the pearl, while overtone refers to one or more translucent colors that overlie the body color (like blush on a woman’s cheek). A third component of some pearls’ color is orient. When present, it looks like a moving iridescence on or just below a pearl’s surface. * Luster: This is the intensity of light reflected from a pearl’s surface. In general, more lustrous pearls will have a higher value. GIA uses the terms excellent, good, and fair to describe luster on cultured pearls. * Surface Grading: This factor looks at the blemishes, or surface irregularities, on a pearl. Typical blemishes include bumps, abrasions, and spots; the visibility of the irregularities will affect the cost. Very few pearls, however, are completely free of blemishes. * Nacre Quality: Fine nacre quality means that a cultured pearl has a reasonable thickness of nacre around the nucleus as well as a high luster. * Matching : This is the uniformity of appearance in strands and multi-pearl pieces of jewelry, and is judged by the consistency of all of the above factors.

Type 1 Gemstones

The following gemstones are typically inclusion free, even minor inclusions detract from their value.

Diamond, Amethyst, Beryls(Aquamarine,Morganite), Citrine, Smoky Quartz, topaz, Chrysoberyl, Kunzite, Tanzanite, green Tourmaline, and Blue Zircon

IF	Internally flawless under extreme magnification (Very rare)
F	Flawless
VVS	Minute inclusions under 10x; invisible to the unaided eye
VS	Minor inclusions under 10x; usually invisible to the unaided eye
SI1	Noticeable inclusions under 10x; usually visible to the unaided eye
SI2	Noticeable inclusions under 10x; usually quite visible to the unaided eye
I1	prominent- moderate affect on appearance or durability
I2	prominent - severe affect on appearance or durability
I3	prominent- severe affect on beauty, transparency or durability

Type 2 Gemstones

Gemstones that normally have small inclusions that do not detract from value.

Alexandrite, Andalusite, Iolite, Peridot, Rhodolite, Ruby, Sapphire, Spinel, Tourmaline, Garnet, Amethyst, Red Zircon, Tsavorite; Blue, Orange, Purple, Yellow and Parti-colored Tourmaline

F	Flawless
VVS	Minor inclusions under 10x; usually invisible to the unaided eye
VS	Noticeable inclusions under 10x; often invisible to the unaided eye
SI1	Obvious inclusions under 10x; visible to the unaided eye
SI2	Obvious inclusions under 10x; very apparent to the unaided eye
I1	prominent - moderate affect on appearance or durability
I2	prominent - severe affect on appearance or durability
I3	prominent - severe affect on beauty, transparency or durability

6 mm = 1/4 inch (Approx)

存貨單位
尺寸（毫米）: x x mm
重量 (cts)
Certified Gemstones: 不
類型: Bead
顏色

DESCRIPTION:
Gem Type:NATURAL SHELL	Weight (CARATS):39.6 CTS
Color:IVORY TINT	SIZE (mm): 30 X 3 MM
Additional Comments: PIECES- 1 STRAND/ AS IN PHOTO THIS GEM STONE IS NOW IN AUSTRALIA AND WILL BE SHIPPED FROM THERE SO PLEASE BE PATIENT FOR YOUR DELIVERY ARTIFICIAL BLACK DYEING WITH SILVER SALT: Treatment with silver nitrate solutions (AgNO3) is applied since the nineteen thirties to Japanese Akoya cultured pearls. The method was used at the end of the 19th century in the mother-of-pearl industry and natural pearls were also dyed this way. The pearls are immersed for a period of several days or weeks to several months in diluted silver nitrate solution (the dilution ratio is 3 to 4 per cent) and are kept in a dark room. After this, they are exposed to a strong light source (either sun light or artificial light) or they are treated with hydrogen sulphate. Both methods lead to the deposition of metallic silver in an extremely fine distribution in the pearl, causing the dark color. The method enables the production of lighter or darker hues, depending on the quantity of silver produced. An immersion period of several months is required in order to produce truly black colors while shorter periods lead to more brownish or grayish hues. This means that the nucleus remains white, while the outer pearly layer takes on the dark color. The deposition of silver seems to concentrate in the conchioline layer which is often present between the nucleus and the pearly layer. The distribution of silver gets less towards the surface of the pearl. In the case of undrilled pearls diffusion of silver oxide starts however from the surface while in the case of drilled pearls the silver solution will more directly find its way to the border area between nucleus and outer pearly layer. Other Coloration Chinese freshwater cultured pearls in striking artificial colors have been seen on the market since the nineteen eighties. In addition to yellow, there are red, pink, orange brown blue green purple and lilac although rice crispies, baroques and flats were used mainly in the beginning; there have been more rounded shapes also over recent years. Intensely blue, green, yellow, pink, red and purple nearly round pearls, no doubt dyed with chemical agents, have been seen at international trade shows since the late nineteen nineties. No detailed information is available as to the methods used. The colors seem to be permanent and needless to say fall into the lowest price range 7 Pearl Value Factors: * Size: Pearl size is measured in millimeters. Typically, all other factors being equal, a larger pearl of a certain type is more expensive than a smaller one. * Shape: There are three main categories to pearl shape: spherical, symmetrical, and baroque. An example of a symmetrical pearl is an oval, while baroque pearls are irregular in shape. * Color: With cultured pearls, look at body color and, if present, overtone. Bodycolor is the dominant color of the pearl, while overtone refers to one or more translucent colors that overlie the body color (like blush on a woman’s cheek). A third component of some pearls’ color is orient. When present, it looks like a moving iridescence on or just below a pearl’s surface. * Luster: This is the intensity of light reflected from a pearl’s surface. In general, more lustrous pearls will have a higher value. GIA uses the terms excellent, good, and fair to describe luster on cultured pearls. * Surface Grading: This factor looks at the blemishes, or surface irregularities, on a pearl. Typical blemishes include bumps, abrasions, and spots; the visibility of the irregularities will affect the cost. Very few pearls, however, are completely free of blemishes. * Nacre Quality: Fine nacre quality means that a cultured pearl has a reasonable thickness of nacre around the nucleus as well as a high luster. * Matching : This is the uniformity of appearance in strands and multi-pearl pieces of jewelry, and is judged by the consistency of all of the above factors.