Diamond Polish and Symmetry: Guide to GIA Terminology and Abbreviations

Polish Features

Polish Feature	Abbreviation	Definition	Example
Abrasion	Abr	An area of minute scratches or pits along a facet edge producing a fuzzy white line instead of a sharp facet junction
Burn	Brn Dop	Whitish haze caused by excessive heat during polishing or, occasionally, by a jeweler’s torch is listed as “Brn.” A burn mark caused by excessive heat at the location where the dop touched the diamond is referred to more specifically as “Dop.”
Laser Manufacturing Remnant	LMR	A remnant of laser manufacturing that remains on the surface of the polished diamond; typically appears as a transparent or white groove; only considered polish when it does not penetrate into the diamond at 10x magnification.
Lizard Skin	LS	A transparent, uneven texture confined to one facet caused by polishing a facet off-grain
Nick	Nck	A small notch on a facet junction, usually along the girdle or at the culet
Pit	Pit	A tiny opening appearing as a white dot
Rough Girdle	RG	An irregular pitted or granular surface of a bruted girdle due to pits and nicks
Scratch	Scr	A surface mark, normally seen as a fine white line that may be curved or straight
Polish Lines	Wht TP Drag line Polish mark	Parallel lines left by the polishing process; may appear white (Wht) or transparent (TP). A heavy transparent polish line off a surface-reaching feature is referred to more specifically as a "drag line". A surface feature made during the polishing process that resembles an extra facet without a distinct or straight facet junction is referred to as a "polish mark".	A surface feature made during the polishing process that resembles an extra facet without a distinct or straight facet junction is referred to as a "polish mark"." title="Parallel lines left by the polishing process; may appear white (Wht) or transparent (TP). A heavy transparent polish line off a surface-reaching feature is referred to more specifically as a "drag line". A surface feature made during the polishing process that resembles an extra facet without a distinct or straight facet junction is referred to as a "polish mark"." />

Polish Feature Locations

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Symmetry Feature	Abbreviation	Definition	Example
Crown Angle Variation	CV	Unequal crown angles
Crown Height Variation	CHV	Girdle plane not parallel to the table causing uneven crown height
Culet Off-Center	C/oc	Deviation of the culet from the central position on the pavilion
Extra Facet	EF	Additional facet placed without regard for symmetry and not required by the cutting style
Girdle Thickness Variation	GTV	Variation of the girdle thickness at the bezel-main positions
Lower Half Percentage Variation	LPV	Variation of lower half facet length percentages
Lower Half Variation	LHV	Unequal lower half facet angles
Misalignment	Aln	Displacement of the crown and pavilion facets in relation to each other
Misshapen Facet	Fac MB MS MM	Difference in shape or size between one facet and another of the same type, or distortion of a given facet; bezel, star and main facets that are misshapen are listed more specifically as misshapen bezel (MB), misshapen star (MS) and misshapen main (MM)
Missing Facet	MF	Asymmetrically missing facet
Natural	N	Part of the original rough diamond’s surface that remains on the polished diamond
Non-Octagonal Table	T/oct TEV	The table of a Round Brilliant is not a regular octagon, showing differences among the four table sizes (T/oct) or among the eight table edges (TEV)
Non-Pointing	Ptg SM SB OM OB	Fully formed facet that does not reach its prescribed location (short facet) or is incompletely finished (open facet), resulting in adjoining facets not meeting at precise points; non-pointing of bezel and main facets are listed more specifically as short main (SM), short bezel (SB), open main (OM) and open bezel (OB)
Out-of-Round	OR	Deviation from the circular shape of a round diamond
Pavilion Depth Variation	PDV	Variation of pavilion depth
Pavilion Angle Variation	PV	Unequal pavilion angles
Star Percentage Variation	SPV	Variation of star facet length percentages
Star Angle Variation	SV	Unequal star facet angles
Table Off-Center	T/oc	Deviation of the table from the central position on the crown
Table/Culet Alignment	T/C	Displacement of the table facet and culet in different directions
Upper Half Variation	UHV	Unequal upper half facet angles
Uneven Outline	UO	Asymmetrical shape outline; also refers to bumps and flattened areas created by a natural, extra facet or uneven girdle faceting on round diamonds

Cumulative

Cumulative is listed under symmetry features when the symmetry grade is based on the combined effect of symmetry features instead of individual deviations. For example, a diamond with pavilion depth variation (PDV) and crown angle variation (CV) that measures on the border of Very Good and Good may receive a lower symmetry grade based on their combined appearance and be represented as “Cumulative: PDV, CV.”

*Reports for all diamonds graded later than January 30th, 2012 should include only the terminology and abbreviations listed in this document. You may come across non-standardized information on diamonds graded prior to January 30th, 2012 including the use of the modifiers listed in the table above.

“Sl” and “+” were typically applied to both Polish features and Symmetry deviations, while “fnt” and “hvy” were applied exclusively to Polish features. The modifier “+” referred to multiple facets of the same type with a given polish feature, or multiple facets of the same type with a given symmetry deviation (Ex. TP: l.h.+; MM+).