Seven Value Factors

In the pearl business, you’ll often see a farmer, dealer, retailer, or experienced customer pick up a single pearl and examine it closely while slowly rotating it in the tips of the thumb, index, and middle fingers. Or you might see someone pick up a strand of pearls, hold a looped end with one hand and slowly draw the strand across the open palm of the other hand while closely examining the individual pearls.

These are the ways that pearl professionals judge the size and quality of a single pearl or of the pearls in a strand. Size and quality determine value. The characteristics used to assess the beauty and value of a pearl and contribute to a judgment of its quality are called value factors.

TheGemological Institute of America (GIA) has developed a universally accepted objective system that helps people grade pearls. It consists of seven value factors: size, shape, color, luster, surface, nacre thickness, and matching. The last factor, matching, doesn’t apply to single pearls or intentionally mismatched pearls. It measures the uniformity of appearance of two or more pearls that are intended to look alike.

Below is a breakdown of the component parts of the seven value factors (starting with size) spelled out  by the GIA:

1.    Size

                        If all other value factor are equal, the larger pearl will hold the most value.  In the business of pearls, bigger is usually better.

2.  Shape

a.     There are Seven Standard Shapes acknowledged by the GIA

                                                    i. Round

                                                    ii. Near Round

                                                    iii. Oval

                                                    iv. Button

                                                    v. Drop

                                                    vi. Semi Baroque

vii. Baroque

b.    Any shape other than above are called “Fancy."

c.    The term "Round" has very tight tolerances and therefore most pearls fall within the Near Round category.  For example:  with Chinese Freshwater Pearls  only 1 pearl in 500,000 are considered Round

         3.  Color

a.     There are Three Components of Color

                                                       i.      Hue—the basic impression of color (e.g. blue, green, yellow)

                                                       ii.     Tone—Color’s lightness/darkness

                                                       iii.    Saturation—Color’s strength or intensity

b.    There are Three Characteristics of Color

                                                       i.      Bodycolor—the dominant or overall color of the pearl.   GIA breaks bodycolor down into three categories:

                                                                                1.     Neutral—White, Gray, Black

                                                                                2.     Near Neutral—Silver, Cream, Brown

                                                                                3.     Hues—All Others (GIA recognizes 19)

                                                       ii.     Overtone—Overtone is a translucent color that appears on the surface of the pearl (most common: green,                                                                                         blue, pink)

                                                       iii.    Orient—Orient is surface iridescence or maybe more simply defined as sparkle.

c.     What colors are considered to be the High Value Colors of each type of pearl?

                                                       i.      Akoya—Silver and White

                                                       ii.     Freshwater—While and Purple

                                                       iii.    Tahitian—Peacock and Aubergine

                                                       iv.    South Sea—Silver and Gold

         4.  Luster

a.     Of  all the value factors designated by the Gemological Institute of America (GIA), Luster might be the most important

b.    Luster is determined by

                                                       i.     Thickness, quality and composition of nacre (thick is not necessarily better)

                                                       ii.    Speed of nacre deposition (the slower, the better)

                                                       iii.   Species and health of mollusk

                                                       iv.   Regularity of layers (tight uniform layers = high quality)

c.    GIA has identified five different categories of Luster

                                                       i.      Excellent

                                                       ii.     Very Good

                                                       iii.    Good

                                                       iv.    Fair

                                                       v.     Poor

         5.  Surface Quality

a.     GIA has specified Ten different Types of Blemishes

                                                       i.     Abrasion--A series of scratches on the surface of the pearl.

                                                       ii.    Bump--An irregular bulge usually too small to effect the basic shape.

                                                       iii.   Chip--An opening or a cavity in the surface.

                                                       iv.   Crack--A fracture in either the nacre (outside layer) or the nucleus (inside bead).

                                                       v.    Flat--A flat section on an otherwise consistently spherical pearl.

                                                       vi.   Gap--An area where the bead is exposed because of a lack of nacre surface covering.

                                                       vii.  Pit--An indentation or depression in a single pearl or a group of pearls.

                                                       iix.  Scratch--A thin groove cause by extraneous forces.

                                                       ix.   Spot--An area on the pearl that is darker than the surrounding area.

                                                       x.    Wrinkle--An irregular ridge/crease on the surface.

b.    Four Classifications

                                                       i.     Clean (Blemish Free = Spotless)

                                                       ii.    Lightly Spotted

                                                       iii.   Moderately Spotted

                                                       iv.   Heavily Spotted

         6.  Nacre Quality

a.     GIA spells out three different categories of Nacre Quality

                                                       i.      Acceptable

                                                       ii.     Nucleus Visible

                                                       iii.    Chalky Appearance

b.    Thickness is always stated in terms of Per Radius and refers to the distance (normally in millimeters) from the outside surface of the bead to the outside surface of the the pearls.

         7.   Matching

a.     Matching refers to the consistency within a group of pearls most likely on a strand.  GIA has identified Five Classifications of matching

                                                       i.      Excellent

                                                       ii.     Very Good

                                                       iii.    Good

                                                       iv.    Fair

                                                       v.     Poor