Every GIA diamond grading report contains an assessment of a diamond’s polish and symmetry, which are contributing factors in determining the overall quality of a diamond’s finish. In evaluating polish and symmetry, GIA considers their specific features and visibility under 10x magnification. Polish and symmetry are then rated on a scale ranging from Excellent to Poor.
The guide below explains each polish and symmetry feature, along with their abbreviations and the possible locations of polish features on the diamond.
Laboratory clients can view the detailed polish and symmetry assessment for each diamond they submit, by going to the Item Details in My Laboratory.
Polish Features
Polish is graded on a scale from Excellent to Poor based on the presence and visibility of polish features at 10x magnification. The following features are considered in the polish assessment.
| 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
The location of each polish feature is specified using the following terms.
| Location | Abbreviation |
|---|---|
| Bezel Facet | bez |
| Chevron Facet | chevron |
| Crown Corner Step Facet | crown corner step |
| Crown | crown |
| Crown Facet | crown facet |
| Crown Step Facet | crown step |
| Culet | culet |
| Girdle | girdle |
| Half-Moon Facet | half-moon |
| Lower Half Facet | l.h. |
| Pavilion Main Facet | main |
| Pavilion | pav |
| Pavilion Corner Step Facet | pav corner step |
| Pavilion Facet | pav facet |
| Pavilion Step Facet | pav step |
| Star Facet | star |
| Table Facet | table |
| Upper Half Facet | u.h. |
| Location | Abbreviation |
|---|---|
| Bezel Facet | bez |
| Chevron Facet | chevron |
| Crown Corner Step Facet | crown corner step |
| Crown | crown |
| Crown Facet | crown facet |
| Crown Step Facet | crown step |
| Culet | culet |
| Girdle | girdle |
| Half-Moon Facet | half-moon |
| Lower Half Facet | l.h. |
| Pavilion Main Facet | main |
| Pavilion | pav |
| Pavilion Corner Step Facet | pav corner step |
| Pavilion Facet | pav facet |
| Pavilion Step Facet | pav step |
| Star Facet | star |
| Table Facet | table |
| Upper Half Facet | u.h. |
Examples:
Symmetry Features
Symmetry is graded on a scale from Excellent to Poor based on the presence and visibility of symmetry deviations at 10x magnification. The following features are considered in the symmetry assessment.
| 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 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.”
Abbreviations
| Polish Features | |
|---|---|
| Abbreviation | Polish Feature |
| Abr | Abrasion |
| Brn | Burn |
| Dop | Dop Burn |
| LMR | Laser Manufacturing Remnant |
| LS | Lizard Skin |
| Nck | Nick |
| Pit | Pit |
| RG | Rough Girdle |
| Scr | Scratch |
| Wht | White Polish lines |
| TP | Transparent Polish Lines |
| Drag line | |
| Polish mark |
| Polish Features | |
|---|---|
| Abbreviation | Polish Feature |
| Abr | Abrasion |
| Brn | Burn |
| Dop | Dop Burn |
| LMR | Laser Manufacturing Remnant |
| LS | Lizard Skin |
| Nck | Nick |
| Pit | Pit |
| RG | Rough Girdle |
| Scr | Scratch |
| Wht | White Polish lines |
| TP | Transparent Polish Lines |
| Drag line | |
| Polish mark |
| Symmetry Features | |
|---|---|
| Abbreviation | Symmetry Feature |
| Aln | Misalignment |
| C/oc | Culet Off-Center |
| CV | Crown Angle Variation |
| CHV | Crown Height Variation |
| EF | Extra Facet |
| Fac | Misshapen Facet |
| GTV | Girdle Thickness Variation |
| LHV | Lower Half Angle Variation |
| LPV | Lower Half Percentage Variation |
| MB | Misshapen Bezel |
| MF | Missing Facet |
| MM | Misshapen Main |
| MS | Misshapen Star |
| N | Natural |
| OB | Open Bezel |
| OM | Open Main |
| OR | Out-of-Round |
| PDV | Pavilion Depth Variation |
| Ptg | Non-Pointing |
| PV | Pavilion Angle Variation |
| SB | Short Bezel |
| SM | Short Main |
| SPV | Start Percentage Variation |
| SV | Star Angle Variation |
| T/C | Table/Culet Alignment |
| T/oc | Table Off-Center |
| T/oct | Non-Octagonal Table |
| TEV | Table Edge Variation |
| UHV | Upper Half Angle Variation |
| UO | Uneven Outline |
| Symmetry Features | |
|---|---|
| Abbreviation | Symmetry Feature |
| Aln | Misalignment |
| C/oc | Culet Off-Center |
| CV | Crown Angle Variation |
| CHV | Crown Height Variation |
| EF | Extra Facet |
| Fac | Misshapen Facet |
| GTV | Girdle Thickness Variation |
| LHV | Lower Half Angle Variation |
| LPV | Lower Half Percentage Variation |
| MB | Misshapen Bezel |
| MF | Missing Facet |
| MM | Misshapen Main |
| MS | Misshapen Star |
| N | Natural |
| OB | Open Bezel |
| OM | Open Main |
| OR | Out-of-Round |
| PDV | Pavilion Depth Variation |
| Ptg | Non-Pointing |
| PV | Pavilion Angle Variation |
| SB | Short Bezel |
| SM | Short Main |
| SPV | Start Percentage Variation |
| SV | Star Angle Variation |
| T/C | Table/Culet Alignment |
| T/oc | Table Off-Center |
| T/oct | Non-Octagonal Table |
| TEV | Table Edge Variation |
| UHV | Upper Half Angle Variation |
| UO | Uneven Outline |
| Polish Locations | |
|---|---|
| Abbreviation | Polish Location |
| bez | Bezel Facet |
| chevron | Chevron Facet |
| crown corner step | Crown Corner Step Facet |
| crown | Crown |
| crown facet | Crown Facet |
| crown step | Crown Step Facet |
| culet | Culet |
| girdle | Girdle |
| half-moon | Half-Moon Facet |
| l.h. | Lower Half Facet |
| main | Pavilion Main Facet |
| pav | Pavilion |
| pav corner step | Pavilion Corner Step Facet |
| pav facet | Pavilion Facet |
| pav step | Pavilion Step Facet |
| star | Star Facet |
| table | Table Facet |
| u.h. | Upper Half Facet |
| Polish Locations | |
|---|---|
| Abbreviation | Polish Location |
| bez | Bezel Facet |
| chevron | Chevron Facet |
| crown corner step | Crown Corner Step Facet |
| crown | Crown |
| crown facet | Crown Facet |
| crown step | Crown Step Facet |
| culet | Culet |
| girdle | Girdle |
| half-moon | Half-Moon Facet |
| l.h. | Lower Half Facet |
| main | Pavilion Main Facet |
| pav | Pavilion |
| pav corner step | Pavilion Corner Step Facet |
| pav facet | Pavilion Facet |
| pav step | Pavilion Step Facet |
| star | Star Facet |
| table | Table Facet |
| u.h. | Upper Half Facet |
| Modifiers* | |
|---|---|
| Abbreviation | Modifier |
| sl | slight |
| fnt | faint |
| hvy | heavy |
| + | multiple |
| Modifiers* | |
|---|---|
| Abbreviation | Modifier |
| sl | slight |
| fnt | faint |
| hvy | heavy |
| + | multiple |
*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+).
Every GIA diamond grading report contains an assessment of a diamond’s polish and symmetry, which are contributing factors in determining the overall quality of a diamond’s finish. In evaluating polish and symmetry, GIA considers their specific features and visibility under 10x magnification. Polish and symmetry are then rated on a scale ranging from Excellent to Poor.
The guide below explains each polish and symmetry feature, along with their abbreviations and the possible locations of polish features on the diamond.
Laboratory clients can view the detailed polish and symmetry assessment for each diamond they submit, by going to the Item Details in My Laboratory.
Polish Features
Polish is graded on a scale from Excellent to Poor based on the presence and visibility of polish features at 10x magnification. The following features are considered in the polish assessment.
| 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
The location of each polish feature is specified using the following terms.
| Location | Abbreviation |
|---|---|
| Bezel Facet | bez |
| Chevron Facet | chevron |
| Crown Corner Step Facet | crown corner step |
| Crown | crown |
| Crown Facet | crown facet |
| Crown Step Facet | crown step |
| Culet | culet |
| Girdle | girdle |
| Half-Moon Facet | half-moon |
| Lower Half Facet | l.h. |
| Pavilion Main Facet | main |
| Pavilion | pav |
| Pavilion Corner Step Facet | pav corner step |
| Pavilion Facet | pav facet |
| Pavilion Step Facet | pav step |
| Star Facet | star |
| Table Facet | table |
| Upper Half Facet | u.h. |
| Location | Abbreviation |
|---|---|
| Bezel Facet | bez |
| Chevron Facet | chevron |
| Crown Corner Step Facet | crown corner step |
| Crown | crown |
| Crown Facet | crown facet |
| Crown Step Facet | crown step |
| Culet | culet |
| Girdle | girdle |
| Half-Moon Facet | half-moon |
| Lower Half Facet | l.h. |
| Pavilion Main Facet | main |
| Pavilion | pav |
| Pavilion Corner Step Facet | pav corner step |
| Pavilion Facet | pav facet |
| Pavilion Step Facet | pav step |
| Star Facet | star |
| Table Facet | table |
| Upper Half Facet | u.h. |
Examples:
Symmetry Features
Symmetry is graded on a scale from Excellent to Poor based on the presence and visibility of symmetry deviations at 10x magnification. The following features are considered in the symmetry assessment.
| 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 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.”
Abbreviations
| Polish Features | |
|---|---|
| Abbreviation | Polish Feature |
| Abr | Abrasion |
| Brn | Burn |
| Dop | Dop Burn |
| LMR | Laser Manufacturing Remnant |
| LS | Lizard Skin |
| Nck | Nick |
| Pit | Pit |
| RG | Rough Girdle |
| Scr | Scratch |
| Wht | White Polish lines |
| TP | Transparent Polish Lines |
| Drag line | |
| Polish mark |
| Polish Features | |
|---|---|
| Abbreviation | Polish Feature |
| Abr | Abrasion |
| Brn | Burn |
| Dop | Dop Burn |
| LMR | Laser Manufacturing Remnant |
| LS | Lizard Skin |
| Nck | Nick |
| Pit | Pit |
| RG | Rough Girdle |
| Scr | Scratch |
| Wht | White Polish lines |
| TP | Transparent Polish Lines |
| Drag line | |
| Polish mark |
| Symmetry Features | |
|---|---|
| Abbreviation | Symmetry Feature |
| Aln | Misalignment |
| C/oc | Culet Off-Center |
| CV | Crown Angle Variation |
| CHV | Crown Height Variation |
| EF | Extra Facet |
| Fac | Misshapen Facet |
| GTV | Girdle Thickness Variation |
| LHV | Lower Half Angle Variation |
| LPV | Lower Half Percentage Variation |
| MB | Misshapen Bezel |
| MF | Missing Facet |
| MM | Misshapen Main |
| MS | Misshapen Star |
| N | Natural |
| OB | Open Bezel |
| OM | Open Main |
| OR | Out-of-Round |
| PDV | Pavilion Depth Variation |
| Ptg | Non-Pointing |
| PV | Pavilion Angle Variation |
| SB | Short Bezel |
| SM | Short Main |
| SPV | Start Percentage Variation |
| SV | Star Angle Variation |
| T/C | Table/Culet Alignment |
| T/oc | Table Off-Center |
| T/oct | Non-Octagonal Table |
| TEV | Table Edge Variation |
| UHV | Upper Half Angle Variation |
| UO | Uneven Outline |
| Symmetry Features | |
|---|---|
| Abbreviation | Symmetry Feature |
| Aln | Misalignment |
| C/oc | Culet Off-Center |
| CV | Crown Angle Variation |
| CHV | Crown Height Variation |
| EF | Extra Facet |
| Fac | Misshapen Facet |
| GTV | Girdle Thickness Variation |
| LHV | Lower Half Angle Variation |
| LPV | Lower Half Percentage Variation |
| MB | Misshapen Bezel |
| MF | Missing Facet |
| MM | Misshapen Main |
| MS | Misshapen Star |
| N | Natural |
| OB | Open Bezel |
| OM | Open Main |
| OR | Out-of-Round |
| PDV | Pavilion Depth Variation |
| Ptg | Non-Pointing |
| PV | Pavilion Angle Variation |
| SB | Short Bezel |
| SM | Short Main |
| SPV | Start Percentage Variation |
| SV | Star Angle Variation |
| T/C | Table/Culet Alignment |
| T/oc | Table Off-Center |
| T/oct | Non-Octagonal Table |
| TEV | Table Edge Variation |
| UHV | Upper Half Angle Variation |
| UO | Uneven Outline |
| Polish Locations | |
|---|---|
| Abbreviation | Polish Location |
| bez | Bezel Facet |
| chevron | Chevron Facet |
| crown corner step | Crown Corner Step Facet |
| crown | Crown |
| crown facet | Crown Facet |
| crown step | Crown Step Facet |
| culet | Culet |
| girdle | Girdle |
| half-moon | Half-Moon Facet |
| l.h. | Lower Half Facet |
| main | Pavilion Main Facet |
| pav | Pavilion |
| pav corner step | Pavilion Corner Step Facet |
| pav facet | Pavilion Facet |
| pav step | Pavilion Step Facet |
| star | Star Facet |
| table | Table Facet |
| u.h. | Upper Half Facet |
| Polish Locations | |
|---|---|
| Abbreviation | Polish Location |
| bez | Bezel Facet |
| chevron | Chevron Facet |
| crown corner step | Crown Corner Step Facet |
| crown | Crown |
| crown facet | Crown Facet |
| crown step | Crown Step Facet |
| culet | Culet |
| girdle | Girdle |
| half-moon | Half-Moon Facet |
| l.h. | Lower Half Facet |
| main | Pavilion Main Facet |
| pav | Pavilion |
| pav corner step | Pavilion Corner Step Facet |
| pav facet | Pavilion Facet |
| pav step | Pavilion Step Facet |
| star | Star Facet |
| table | Table Facet |
| u.h. | Upper Half Facet |
| Modifiers* | |
|---|---|
| Abbreviation | Modifier |
| sl | slight |
| fnt | faint |
| hvy | heavy |
| + | multiple |
| Modifiers* | |
|---|---|
| Abbreviation | Modifier |
| sl | slight |
| fnt | faint |
| hvy | heavy |
| + | multiple |
*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+).
