Polish Good (Pol G)
Polish Good (Pol G)
The mid-tier GIA polish grade with minor marks visible at 10×
Polish Good, abbreviated Pol G on a GIA diamond grading report, is the middle grade in GIA's five-tier polish scale, sitting between Very Good and Fair. A stone graded Pol G shows minor polish marks visible at 10× magnification, but the marks do not significantly affect brilliance or overall appearance to the unaided eye. The grade represents commercial-quality work falling short of the standard expected for premium goods.
What it indicates
Polish Good stones typically display a small number of polish lines on selected facets, light abrasions on facet junctions, or faint surface graining marks. The defects are present and identifiable to a trained grader at 10×, but they are minor enough that brilliance and light return are not noticeably reduced. Most observers without magnification will see the stone as fully polished.
The grade is acceptable in commercial-quality diamonds and in budget jewellery production, where the price tier does not justify the additional cutting time required for Very Good or Excellent finishes. Older cuts and stones from less rigorous polishing centres are also more often graded Pol G than the contemporary output of established Indian, Israeli, and Belgian factories.
Market position
Pol G commands a smaller discount relative to Pol VG than the Pol F grade does, reflecting the smaller difference in actual polish quality between the two grades. The market accepts Pol G for everyday commercial goods and price-sensitive bridal sales, although the grade is generally avoided in stones above two carats and in stones intended for the premium tier of the market. For most retail customers, the practical decision is whether to pay the premium for Pol VG; the visible difference in the finished stone is usually too small to justify it for stones at the smaller end of the size range.
Cut grade interaction
GIA's overall cut grade for round-brilliant diamonds takes polish into account as one of its inputs. A stone with Pol G is capped at a cut grade of Very Good, regardless of how favourable its proportions otherwise are. Stones aiming for an Excellent overall cut grade therefore need both polish and symmetry at Very Good or higher. This linkage is one of the principal reasons modern diamond cutters target Very Good or Excellent polish as the production standard.