Defining Diamond Clarity
Clarity refers to the presence, visibility, and characteristics of inclusions (internal features) and blemishes (surface features) in diamonds. The clarity grading system evaluates these characteristics under 10× magnification using standardized methodology developed by the Gemological Institute of America.
Most diamonds contain some inclusions—they are natural consequences of crystal formation, whether geological or laboratory. Inclusions do not necessarily indicate poor quality; many high-value diamonds contain minor inclusions invisible without magnification.
Clarity grading considers five factors: size (larger inclusions lower clarity grade), number (more inclusions lower grade), position (center inclusions more visible than edge inclusions), nature (type and severity of inclusion), and relief (contrast between inclusion and surrounding diamond).
The Clarity Grading Scale
GIA's clarity scale ranges from Flawless (FL) to Included 3 (I3), with 11 distinct grades. The scale applies identically to natural and laboratory-grown diamonds.
Flawless and Internally Flawless (FL, IF)
Flawless (FL): No inclusions or blemishes visible under 10× magnification by a skilled grader. Extremely rare—less than 1% of diamonds achieve FL grade. Surface blemishes that can be removed by minor repolishing do not prevent FL grade.
Internally Flawless (IF): No inclusions visible under 10× magnification; only insignificant surface blemishes present. Slightly less rare than FL but still uncommon. IF diamonds appear identical to FL diamonds to anyone except trained graders with magnification.
FL and IF diamonds command premium prices due to rarity but offer no visual advantage over lower clarity grades in normal viewing conditions.
Very Very Slightly Included (VVS1, VVS2)
VVS1: Minute inclusions extremely difficult for skilled graders to see under 10× magnification. Inclusions might include tiny pinpoints, faint clouds, or internal graining visible only from the pavilion (bottom) view.
VVS2: Minute inclusions very difficult for skilled graders to see under 10× magnification. Slightly more visible or numerous than VVS1 but still extremely minor.
VVS grades represent exceptional clarity. Inclusions are invisible to the naked eye and challenging even for professionals with magnification. VVS diamonds appear flawless in all normal viewing situations.
Very Slightly Included (VS1, VS2)
VS1: Minor inclusions difficult for skilled graders to see under 10× magnification. Inclusions might include small crystals, clouds, or feathers that require careful examination to locate.
VS2: Minor inclusions somewhat easy for skilled graders to see under 10× magnification but still difficult for untrained observers. Inclusions are typically invisible to the naked eye.
VS grades offer excellent value—inclusions remain invisible without magnification while prices are significantly lower than VVS or IF grades. VS2 represents a popular choice balancing clarity and cost.
Slightly Included (SI1, SI2)
SI1: Noticeable inclusions easy for skilled graders to see under 10× magnification. Many SI1 diamonds are "eye-clean" (no visible inclusions without magnification), though this varies by inclusion type, position, and diamond size.
SI2: Noticeable inclusions very easy to see under 10× magnification. Some SI2 diamonds show inclusions visible to the naked eye, particularly in larger stones or with dark/centrally located inclusions. Eye-clean SI2 diamonds exist but require careful selection.
SI grades require individual evaluation. Some SI1 diamonds appear flawless without magnification; others show visible inclusions. Examine specific diamonds rather than relying solely on grade.
Included (I1, I2, I3)
I1: Obvious inclusions visible under 10× magnification and usually visible to the naked eye. Inclusions may affect transparency and brilliance in some cases.
I2: Obvious inclusions easily visible to the naked eye that may affect transparency, brilliance, or durability.
I3: Prominent inclusions very easily visible to the naked eye that significantly affect transparency, brilliance, and potentially durability.
Included grades show visible inclusions that impact appearance. I1 diamonds may still be acceptable for smaller stones or specific applications, while I2 and I3 grades typically show significant visual impact.
Types of Diamond Inclusions
Inclusions vary in type, appearance, and impact on clarity grade. Understanding inclusion types helps evaluate clarity reports and individual diamonds.
Common Natural Diamond Inclusions
Crystals: Mineral crystals trapped during diamond formation. May appear as dark (graphite, magnetite) or colorless (diamond) crystals. Size and position determine clarity impact.
Clouds: Clusters of tiny pinpoint inclusions creating hazy areas. Light clouds have minimal impact; dense clouds can affect transparency.
Feathers: Internal fractures or cleavages. Small feathers have minimal impact; large feathers near edges may affect durability.
Pinpoints: Tiny crystals appearing as dots under magnification. Single pinpoints have minimal impact; clusters may form clouds.
Needles: Long, thin mineral crystals. Usually white or transparent, creating minimal visual impact unless numerous or dark.
Twinning wisps: Series of pinpoints, clouds, or crystals along crystal growth planes. Common in natural diamonds.
Laboratory Diamond Inclusion Characteristics
Laboratory-grown diamonds contain different inclusion types reflecting their formation environments:
HPHT inclusions:
- Metallic flux: Dark pinpoints of metal catalyst (iron, nickel, cobalt) trapped during growth
- Graphite: Carbon that didn't crystallize as diamond
- Growth sector boundaries: Zones where different crystal sectors meet
CVD inclusions:
- Planar defects: Thin parallel planes where growth conditions varied
- Silicon inclusions: Silicon from chamber components
- Graphite particles: Non-diamond carbon
CVD and HPHT growth methods produce characteristic inclusion patterns that gemological laboratories use to identify origin, though inclusion types don't affect clarity grading standards—a VS2 grade indicates the same visibility level regardless of inclusion type or origin.
Clarity Grading Methodology
Gemological laboratories follow standardized procedures to ensure consistent clarity grading across different graders and facilities.
Grading Environment and Equipment
Clarity grading occurs under controlled conditions: 10× magnification (standard jeweler's loupe or microscope), neutral lighting (daylight-equivalent fluorescent or LED), and clean diamonds (oil and dirt removed). Graders examine diamonds from multiple angles—table-up, pavilion-up, and profile views.
The 10× magnification standard was established because it represents practical magnification for jewelers and provides consistent grading baseline. Higher magnification would reveal additional inclusions but isn't used for standard grading.
Grading Consistency and Variability
Clarity grading involves human judgment of characteristics that exist on continua rather than in discrete categories. The same diamond submitted to different graders or laboratories may receive grades that vary by one grade (e.g., VS1 vs. VS2) or occasionally two grades for borderline stones.
This variability reflects the inherent limitations of subjective grading rather than grader error. Certification from recognized laboratories (GIA, IGI, GCAL) provides reliable grading within this natural variability range.
Visual Impact and Eye-Clean Diamonds
"Eye-clean" describes diamonds with no inclusions visible to the naked eye under normal viewing conditions (approximately 10-12 inches viewing distance in good lighting). Eye-clean status matters more for appearance than technical clarity grade.
Factors Affecting Eye-Clean Status
Clarity grade: FL through VS2 diamonds are typically eye-clean. SI1 diamonds are often eye-clean; SI2 varies significantly. I1 and below usually show visible inclusions.
Inclusion type: White or transparent inclusions are less visible than dark inclusions. Clouds affect transparency differently than crystals.
Inclusion position: Center inclusions are more visible than edge inclusions. Inclusions under the table are more visible than those under crown facets.
Diamond size: Inclusions become more visible in larger diamonds. A SI2 grade may be eye-clean in a 0.50 ct diamond but visible in a 2.00 ct diamond.
Diamond shape: Step cuts (emerald, Asscher) show inclusions more readily than brilliant cuts due to larger facets and different light patterns.
Selecting Eye-Clean Diamonds
When clarity grade allows variability in eye-clean status (SI1, SI2), examine specific diamonds rather than relying on grade alone. Request high-resolution images or videos showing the diamond from multiple angles. Ask vendors explicitly whether specific diamonds are eye-clean.
For online purchases, verify return policies allow inspection and return if diamonds aren't eye-clean as expected. Reputable vendors provide accurate eye-clean assessments.
Clarity and Diamond Value
Clarity significantly affects diamond pricing, with higher clarity grades commanding premiums. However, the relationship isn't linear—the price difference between FL and IF is smaller than the difference between VS2 and SI1 in many cases.
Optimal Clarity for Value
VS2 and SI1 grades often provide optimal value—high enough clarity to ensure eye-clean appearance in most cases while avoiding the premiums for VVS and IF grades that provide no visual advantage.
For smaller diamonds (under 0.75 ct), SI2 may offer excellent value if eye-clean. For larger diamonds (2.00+ ct), VS1 or higher may be necessary to ensure eye-clean appearance.
Prioritize eye-clean appearance over technical grade. An eye-clean SI1 diamond provides better value than a VS1 diamond with the same appearance at higher cost.
Clarity in Natural vs. Lab-Grown Diamonds
Both natural and laboratory-grown diamonds span the full clarity range from FL to I3. Clarity grading standards apply identically to both—a VS2 grade indicates the same inclusion visibility whether the diamond is natural or lab-grown.
Certification laboratories apply identical clarity grading standards to lab-grown and natural diamonds, using the same 10× magnification, grading environment, and evaluation criteria.
Statistical distributions differ slightly: laboratory diamonds, particularly CVD diamonds, achieve high clarity grades (VVS, IF) more frequently than natural diamonds due to controlled growth conditions. However, both types produce diamonds across all clarity grades.
Inclusion types differ between natural and lab-grown diamonds, but clarity grades reflect visibility level, not inclusion type. A VS2 natural diamond with crystal inclusions and a VS2 lab-grown diamond with planar defects have equivalent inclusion visibility under 10× magnification.
Clarity Enhancement and Treatments
Some diamonds undergo treatments to improve apparent clarity. Treated diamonds must be disclosed on certification reports and in sales transactions.
Laser Drilling
Laser drilling creates microscopic channels from the diamond surface to dark inclusions, allowing bleaching agents to lighten the inclusions. The drill holes remain permanent but are typically microscopic. Laser-drilled diamonds must be disclosed and typically sell at discounts to untreated equivalents.
Fracture Filling
Fracture filling injects glass-like substances into surface-reaching fractures to make them less visible. Fillings can be damaged by heat (jewelry repair) or ultrasonic cleaning. Fracture-filled diamonds require disclosure and sell at significant discounts.
Reputable certification laboratories identify treatments and note them on grading reports. Avoid purchasing diamonds with undisclosed treatments or from vendors unwilling to provide treatment information.
Clarity Plotting and Certification Reports
Certification reports include clarity plots—diagrams showing inclusion locations, types, and characteristics. Plots use standardized symbols: red for internal inclusions, green for surface blemishes.
Clarity plots help verify that the certified diamond matches the physical stone (inclusions should match plotted locations) and understand which inclusions determined the clarity grade. Not all inclusions are plotted—only those affecting the grade or useful for identification.
Lab-grown and natural diamonds receive identical clarity documentation, with plots showing inclusion locations and types regardless of origin.
Frequently Asked Questions
What clarity grade should I choose for an engagement ring?
For most engagement rings, VS2 or SI1 clarity provides optimal value—high enough to ensure eye-clean appearance while avoiding premiums for higher grades that offer no visual advantage. For diamonds under 1.00 ct, SI1 or even SI2 may be eye-clean and offer excellent value. For diamonds over 2.00 ct, consider VS1 or higher to ensure eye-clean status. Prioritize eye-clean appearance over technical grade, and examine specific diamonds rather than relying solely on clarity grade.
Can you see inclusions in VS2 diamonds without magnification?
No, VS2 diamonds are typically eye-clean—inclusions are not visible to the naked eye under normal viewing conditions. VS2 inclusions are "somewhat easy" for trained graders to see under 10× magnification but remain invisible without magnification in the vast majority of cases. VS2 represents an excellent clarity grade balancing appearance and value, as it provides visually flawless appearance at significantly lower cost than VVS or IF grades.
Are lab-grown diamonds always higher clarity than natural diamonds?
No. Lab-grown diamonds span the full clarity range from FL to I3, just like natural diamonds. Controlled laboratory conditions can produce high-clarity stones more consistently than geological processes, so laboratory diamonds (particularly CVD) achieve VVS and IF grades more frequently on average. However, many lab-grown diamonds contain inclusions and receive VS, SI, or I grades. Clarity depends on specific growth conditions, not production method. Always verify clarity grade on certification reports rather than assuming lab-grown diamonds are automatically high clarity.
Do inclusions affect diamond durability or strength?
Most inclusions have minimal impact on durability. Small crystals, pinpoints, clouds, and needles don't affect structural integrity. Large feathers (fractures) near edges or extending to the surface may create potential weak points, particularly if subjected to sharp impacts. I2 and I3 clarity diamonds with large, numerous inclusions may have reduced durability. For clarity grades VS2 and above, inclusions don't meaningfully affect durability—diamonds remain highly durable regardless of minor inclusions.
What does "eye-clean" mean and why does it matter?
"Eye-clean" means no inclusions are visible to the naked eye under normal viewing conditions (10-12 inches viewing distance in good lighting). Eye-clean status matters because it determines actual appearance—an eye-clean SI1 diamond looks identical to a VVS1 diamond in normal wear, despite the clarity grade difference. Eye-clean diamonds provide better value than paying premiums for higher clarity grades that offer no visible improvement. When selecting diamonds in SI1-SI2 range, verify eye-clean status for specific stones rather than relying on grade alone.
References
This article references clarity grading standards from:
- Gemological Institute of America (GIA) clarity grading methodology and standards
- International Gemological Institute (IGI) clarity grading protocols
- American Gem Society (AGS) clarity grading system
- Gems & Gemology peer-reviewed articles on inclusion characterization
- GIA Diamond Grading Course materials and training standards
- Research on clarity grading consistency and reproducibility
- Inclusion identification and classification systems