kristin
07-14-2006, 10:22 AM
The GIA Pearl Grading classification system has 7 value factors.
The Seven Pearl Value Factors are:
Size- Pearls are measured in millimeters rounded to the nearest 0.5mm.
Shape- there are 3 main catagories to pearl shape Spherical, symmetrical, and baroque.There are 7 standard shapes that fall into these catagories.
Spherical-
Round- appears round to the eye
Near round- appears almost round to the eye
Symmetrical-
Oval- symmetrical, rounded, oblong shape
Button- symmetrical, flattened or slightly flattened
circular shape.
Drop- symmetrical, round, pear shape.
Baroque-
Semi-baroque-non symmetrical, off round, slightly
irregular oval, button or drop shape
Baroque- non symmetrical shape - will have a
noticeably irregular appearance.
Color- the most common colors are actually neutral or near neutral colors. Pearl color can have 3 characteristics:
Body Color- the dominant overall color of the pearl
Overtone- one or more transulcent colors that appear over
the body color
Orient -Iridescent, rainbow colors shimmering on or just
below a pearls surface
Luster- luster is the intensity of light reflected from the surface of the pearl. The four catagories of luster are:
Excellent - reflections are bright, sharp, and distinct.
Good- reflections are bright, but not sharp, they are slightly
hazy around the edges
Fair- reflections are weak, hazy and blurred.
Poor- reflections are dim and diffused
Surface Quality- surface quality is the condition of the pearl's surface. Blemishes or irregularities are characteristic to pearls and are usually confined to the surface. There are 4 surface quality classifications:
Clean- pearls can be blemish free or contain minute surface
characteristics that are difficult for a trained observer to see
Lightly Blemished- pearls show minor surface irregularities
when inspected by trained observer
Moderately Blemished- pearls show noticeable surface
characteristics; a few might be quite noticeable
Heavily Blemished- pearls show obvious surface irregularities.
Durability might be affected.
Nacre Quality- nacre quality is determined by it's thickness and layering. Nacre quality can be classified in 3 ways:
Acceptable- nucleus not noticeable; no chalky appearance
Nucleus Visible- pearl(s) show evidence of bead nucleus
through the nacre; pearl(s) may show blinking when rotated
Chalky Appearance- pearls have an obvious dull appearance
Matching- matching describes the uniformity of pearls in jewelry. This is judged by the consistancy of size, shape, color, luster, surface quality, nacre quality among the pearls in the jewlery. Matching has 3 classifications:
Excellent- peals are uniform in appearance and drilled on
center
Good- minor variations in uniformity; classification is based
on severity of variations
Fair- noticeable variations in uniformity; classification is
based on severity of variations
The Seven Pearl Value Factors are:
Size- Pearls are measured in millimeters rounded to the nearest 0.5mm.
Shape- there are 3 main catagories to pearl shape Spherical, symmetrical, and baroque.There are 7 standard shapes that fall into these catagories.
Spherical-
Round- appears round to the eye
Near round- appears almost round to the eye
Symmetrical-
Oval- symmetrical, rounded, oblong shape
Button- symmetrical, flattened or slightly flattened
circular shape.
Drop- symmetrical, round, pear shape.
Baroque-
Semi-baroque-non symmetrical, off round, slightly
irregular oval, button or drop shape
Baroque- non symmetrical shape - will have a
noticeably irregular appearance.
Color- the most common colors are actually neutral or near neutral colors. Pearl color can have 3 characteristics:
Body Color- the dominant overall color of the pearl
Overtone- one or more transulcent colors that appear over
the body color
Orient -Iridescent, rainbow colors shimmering on or just
below a pearls surface
Luster- luster is the intensity of light reflected from the surface of the pearl. The four catagories of luster are:
Excellent - reflections are bright, sharp, and distinct.
Good- reflections are bright, but not sharp, they are slightly
hazy around the edges
Fair- reflections are weak, hazy and blurred.
Poor- reflections are dim and diffused
Surface Quality- surface quality is the condition of the pearl's surface. Blemishes or irregularities are characteristic to pearls and are usually confined to the surface. There are 4 surface quality classifications:
Clean- pearls can be blemish free or contain minute surface
characteristics that are difficult for a trained observer to see
Lightly Blemished- pearls show minor surface irregularities
when inspected by trained observer
Moderately Blemished- pearls show noticeable surface
characteristics; a few might be quite noticeable
Heavily Blemished- pearls show obvious surface irregularities.
Durability might be affected.
Nacre Quality- nacre quality is determined by it's thickness and layering. Nacre quality can be classified in 3 ways:
Acceptable- nucleus not noticeable; no chalky appearance
Nucleus Visible- pearl(s) show evidence of bead nucleus
through the nacre; pearl(s) may show blinking when rotated
Chalky Appearance- pearls have an obvious dull appearance
Matching- matching describes the uniformity of pearls in jewelry. This is judged by the consistancy of size, shape, color, luster, surface quality, nacre quality among the pearls in the jewlery. Matching has 3 classifications:
Excellent- peals are uniform in appearance and drilled on
center
Good- minor variations in uniformity; classification is based
on severity of variations
Fair- noticeable variations in uniformity; classification is
based on severity of variations