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GIA Seven Pearl Value Factors

There are specific ways to professionally judge the size, quality, beauty, and value using the GIA (Gemology Institute of America) Pearl Description System Value Factors. These factors assist Gem On customers to make an educated decision when comparing and shopping for the correct pearl.

7 GIA Grading Factors

Value Factor 1: Size

Pearls are measured and rounded to the nearest.5mm.
  • Uniformity in a strand is those pearls all nearly the same size, is spherical and measure and vary no more than.5mm. Expressed as example 8.0-8.5mm.
  • Graduated pearls in a strand start with the largest pearl in the center and graduate by small size approaching the clasp. Expressed as example 9.0-5.0mm.
Round Pearl Oval Pearl Baroque Pearl Drop Pearl   Button Pearl
Round Oval Baroque Drop Button


Value Factor 2: Shape

The GIA Shape Description System recognizes 7 specific standardized shapes. Round is in appearance to the un-aided eye. A good way to test a round pearl is measure it’s circumference size with a pearl gauge in several directions and the variation should be less than 2%. Perform the “Eight Way Roller” test by rolling the pearl between your fingers, the pearl should feel round. Round is the most valuable.
  • Rounds are spherical or near spherical.
  • Near Round is slightly out of round, elongated, flattened and almost round.
  • Oval appears symmetrical, almost round and oblong.
  • Button appears symmetrical, flattened or slightly flattened, circular, high and low button in its dome.
  • Drop appears symmetrical, pear shape and can be short or long drop. Drop shape pearls that are clean and excellent luster are very valuable.
  • Baroque has no symmetrical shape and has a noticeable irregularity. These shapes are very popular now because of their uniqueness and one of a kind look. One baroque pearl is certainly a statement of uniqueness and is so trendy in both formal designs as well as formal designs.
  • Semi Baroque appears only slightly symmetrical, are off round, slightly irregular drop, button and oval shape.
  • Circled is a pearl with grooves or ridges that go all the around the pearl and so it is used in nomenclature to combine it’s description with the seven shape factors. As example, round circled, or drop circled.

Value Factor 3: Color

The most important three features of color Gem On Jewelry recommends when purchasing pearls for our customers is to check according to GIA standards: Body color is the overall color of the pearl.
  • Pink will be used for lighter versions of oranges, red, purplish, orangey red
  • Cream will be used for light yellow to light orange
  • Silver for light cool blues
  • Warm Hues typically range for purplish red to greenish yellow with cream and brown hues within this color circle
  • Cool Hues will be reddish purple to yellowish green and with grayish and greenish characteristics sometime nearing the brown hue
Orient occurs when there is more than one translucent color over the body color or surface color. Lastly, overtone is one translucent color over the body color. At Gem On, we follow the GIA Pearl Description System of 19 hues, which describe pearl body colors.At times, we will use the same standards of hue grading with hueish note as part of the name scheme. Any pink on the surface of any other color will be referred to Rose, Green, Blue and Purple are also possibilities

Value Factor 4: Luster

Determine the luster by the way the light is reflected from surface of the pearl. We rate the pearl accordingly to:
  • Excellent: Bright and Sharp Reflections
  • Very Good: Reflection bright and near sharp
  • Good: bright but not sharp
  • Fair: weak and blurred
  • Poor: dim and diffused.

Value Factor 5: Surface

At Gem On we grade the surface of both freshwater and south sea and look for the following: Blemishes:
  • Bump: Blister or welt
  • Chip: Any opening in the cavity of the pearl
  • Spot: Rated as Heavily Spotted, Lightly spotted
  • Flat: often could be a very small flat surface but is not considered to affect the overall shape
  • Crack: Break or fracture in nacre or in the nucleus
  • Pit: Indention or depression
  • Wrinkle: Irregular ridge
  • Scratch: Thin grooves
  • Abrasion: Series of scratches
Surface Classification:
  • CL=Clean: Pearl is blemish – free or has a vey minute characteristic
  • LS = Lightly Spotted: Pearls have “minor” surface irregularities
  • MS=Pearls show “noticeable” surface characteristics, more than few
  • HS=Pearls have “obvious” surface characteristics. Durability of pearl may be compromised

Value Factor 6: Nacre Quality

Gem On Jewelry, LLC will take into account the following three classifications but would like to recommend to customers to select the GIA Pearl Certificate at checkout should they want to confirm nacre thickness.
  • Look for chalky appearances. The pearl will not have reflection but complete chalky appearance
  • Blinking of a pearl will indicate a bead nucleus through the nacre of the pearl
  • Thin nacre will allow the nucleus to be very visible through the nacre and thus is not acceptable by pearl standards

Value Factor 7: Matching

Cultured pearls are naturally occurring and so it is a good idea to keep this mind when checking how the pearls are matched. The impression is to create a perfect necklace that contains pearls of exactly the same qualities of Value Factors 1-6, but many times one or a few pearls may be slightly not the same as the rest of the necklace. It takes many containers or lots of pearls in order to create a one of kind pearl necklace. Gem On Jewelry, LLC achieves the best matching based on these fact sheets.