Polish Fair, abbreviated Pol F on a GIA diamond grading report, is the second-lowest of the five polish grades on GIA's scale, sitting between Good and Poor. A stone graded Pol F shows noticeable polish marks, scratches, or surface irregularities visible at 10× magnification, defects significant enough that they may slightly affect the stone's brilliance and overall appearance under careful observation.

What it indicates

The defects associated with a Fair polish grade typically include prominent polish lines visible across multiple facets, abrasions along facet junctions, and surface graining or burn marks left by aggressive polishing. None of these are usually visible to the unaided eye on a stone of normal size, but they accumulate to the point where the cumulative effect on light return is measurable. A skilled observer at 10× will see the marks immediately.

Fair polish is uncommon in modern cutting. Contemporary diamond manufacturing in established centres aims for Very Good or Excellent polish grades as a matter of standard practice, and stones falling to Fair are generally either older cuts, budget production, or pieces that have been damaged in mounting or wear and not professionally repolished.

Market consequences

A Pol F grade carries a meaningful price discount in the polished-diamond market relative to higher polish grades, particularly for sizes above one carat where polish marks become more visible. The discount applies even when the cut and symmetry grades are otherwise satisfactory, because the polish grade is reported separately and dealers and consumers reading the report react to it independently. Buyers seeking value sometimes accept Pol F deliberately, on the reasoning that the cosmetic effect is invisible without magnification and the price advantage is real.

For investment-grade stones and stones intended for resale through major auction houses, Pol F is generally not acceptable. The expectation at the top of the market is Pol Ex or Pol VG, and a Fair grade is read as a sign that the stone has not received the level of finishing the price would warrant.

Repolishing

Stones with Pol F grades can sometimes be improved through careful repolishing, although this process removes a small amount of weight and may slightly alter proportions. The economics of repolishing depend on the size of the stone and the magnitude of the price difference between Fair and a higher grade, and the calculation is best made by an experienced cutter rather than estimated.

Further reading

• GIA — diamond grading reference
• GIA — diamond cut grading reference
• GIA Gems & Gemology — diamond grading articles