💎 Lab-Grown Diamond Glossary

One of the top diamond certification laboratories, known for its proprietary 0–10 cut grading scale (0 = Ideal). Less commonly used for lab diamonds than GIA or IGI, but highly respected for cut quality assessment.

SHAPE A square step-cut diamond with cropped corners, similar to an emerald cut but squarish. Developed in 1902 by the Asscher Diamond Company. Known for its "hall of mirrors" effect and Art Deco aesthetic. Learn more in our Diamond Shapes Guide.

SETTING A ring setting where a thin metal rim (the bezel) wraps completely around the diamond's girdle, holding it securely. Extremely protective—ideal for active lifestyles. Creates a sleek, modern look. Learn more in our Ring Settings Guide.

CLARITY An imperfection on the surface of a diamond (as opposed to an inclusion, which is internal). Common blemishes include scratches, nicks, and polish lines. Surface blemishes are typically less detrimental to clarity grade than inclusions.

OPTICS The white light reflected from the interior and surface of a diamond. A key component of a diamond's overall sparkle, alongside fire and scintillation. Brilliance is most influenced by cut quality—specifically the proportions of the facets. See also: Fire, Scintillation.

Lab-grown diamonds typically cost 60–80% less than natural diamonds of equivalent quality. This means you can either save significantly or get a much larger stone for the same spend. See our full Engagement Ring Budget Guide for recommended allocations by price range.

4CS The unit of weight for diamonds. One carat = 0.2 grams. Price increases exponentially (not linearly) with carat weight due to rarity thresholds at 0.5, 1.0, 1.5, and 2.0 carats. Often confused with karat (gold purity). Read more: Understanding the 4Cs.

An official document from an independent gemological laboratory (GIA, IGI, AGS) that evaluates a diamond's 4Cs and other characteristics. Always buy a certified diamond—never accept a retailer's self-grading. For lab diamonds, IGI is the most common cert. See our IGI vs GIA guide.

4CS A measure of internal inclusions and surface blemishes. GIA scale (best to worst): FL → IF → VVS1 → VVS2 → VS1 → VS2 → SI1 → SI2 → I1 → I2 → I3. For most buyers, VS2 or SI1 offers the best value—inclusions invisible to the naked eye at a lower price point. Read more: 4Cs Guide.

4CS Graded D (colorless) to Z (light yellow/brown). For lab-grown diamonds, G–I is often the sweet spot—virtually colorless to the naked eye but 15–30% cheaper than D–F. Fancy colored lab diamonds (pink, yellow, blue) are graded on a separate scale. Read more: 4Cs Guide.

A diamond not used to finance armed conflict. While the Kimberley Process certifies this for natural diamonds, it has known loopholes. Lab-grown diamonds are definitively conflict-free by nature—no mining, no supply chain concerns. See: Lab vs Natural Diamonds.

ANATOMY The upper portion of a diamond above the girdle. It contains the table facet (the flat top) and various crown facets. Crown angle and height affect light dispersion and brilliance.

ANATOMY The very bottom point (or small facet) of a diamond. Modern diamonds typically have a pointed culet (graded "None"). A visible culet can appear as a dark circle when viewed face-up, reducing the diamond's apparent quality.

SHAPE A square or rectangular shape with rounded corners and larger facets, resembling a pillow. One of the most popular shapes for lab-grown engagement rings. Known for exceptional brilliance and a romantic, vintage feel. Learn more: Diamond Shapes Guide.

4CS The most important of the 4Cs. Refers to how well a diamond's proportions interact with light—producing brilliance, fire, and scintillation. GIA grades: Excellent → Very Good → Good → Fair → Poor. Always prioritize Excellent or Very Good cut. Read more: 4Cs Guide.

PRODUCTION One of the two main methods for growing lab diamonds. A diamond seed is placed in a chamber filled with carbon-rich gases; microwave energy breaks down the gas and carbon atoms deposit onto the seed layer by layer. CVD produces large, high-quality diamonds efficiently. Compare: HPHT.

ANATOMY The height of a diamond (from culet to table) expressed as a percentage of its width. For a round brilliant, ideal depth is typically 59–62.5%. Too shallow = light leaks from the bottom; too deep = light leaks from the sides, reducing brilliance.

The physical outline of a diamond: round, oval, cushion, princess, emerald, asscher, pear, marquise, radiant, and heart are the most common. Shape is a matter of personal preference but affects price (round is most expensive, up to 20–40% premium) and how inclusions/color show. See: Diamond Shapes Guide.

SHAPE A rectangular step-cut diamond with cropped corners and long, parallel facets. The "hall of mirrors" effect gives it a unique, elegant look. Step cuts show inclusions and color more readily than brilliant cuts, so prioritize VS1+ and G+ for this shape. Learn more: Diamond Shapes Guide.

CLARITY A diamond where inclusions are invisible to the naked eye at normal viewing distance (~25 cm). Not an official grading term—it's a practical buying concept. Most VS2 and many SI1 diamonds are eye-clean. SI2 and below may have visible inclusions. Always check vendor images/video before buying SI grades.

ANATOMY A flat, polished surface on a diamond. A standard round brilliant has 57 or 58 facets. The precise angles and sizes of facets determine how light travels through the stone, directly affecting brilliance, fire, and scintillation.

OPTICS The dispersion of white light into spectral colors (rainbow flashes) as it passes through a diamond's facets. A key component of sparkle alongside brilliance and scintillation. Fire is especially visible in lower lighting conditions. High cut quality maximizes fire.

CLARITY The highest clarity grade—no inclusions or blemishes visible under 10× magnification. Extremely rare and commands a significant price premium. For lab-grown diamonds, FL is far less valuable than for natural diamonds since there's no scarcity. Buying FL for a lab diamond is overkill for most buyers.

The tendency of a diamond to emit a soft glow (usually blue) when exposed to UV light. Graded: None, Faint, Medium, Strong, Very Strong. Strong blue fluorescence can make near-colorless diamonds appear slightly whiter in sunlight—sometimes beneficial, occasionally causing a "milky" or "hazy" look. For lab diamonds, medium fluorescence is generally harmless to appearance. Check retailer images under mixed lighting.

The universal framework for evaluating diamond quality: Cut, Color, Clarity, and Carat weight. Developed by GIA in the 1950s. Cut is the most important. For maximum value on lab diamonds, prioritize in this order: Cut → Color → Clarity → Carat. Read our complete 4Cs Guide.

LAB The world's most respected diamond grading laboratory. Founded in 1931; created the modern 4Cs system. Known for strict, consistent grading. GIA-certified lab diamonds typically cost 20–40% more than IGI-certified stones of the same stated quality. See our comparison: IGI vs GIA for Lab Diamonds.

ANATOMY The outer edge (circumference) of a diamond—the widest part where the crown meets the pavilion. Girdle thickness is graded: Extremely Thin, Very Thin, Thin, Medium, Slightly Thick, Thick, Very Thick, Extremely Thick. Extremely thin girdles are fragile and prone to chipping; extremely thick ones waste carat weight.

See Certification. An official document from GIA, IGI, or AGS evaluating a diamond's quality characteristics. A legitimate grading report includes the diamond's unique ID (often laser-inscribed on the girdle), 4Cs grades, measurements, and a plot of inclusions.

SETTING A ring style where small diamonds (melee) encircle the center stone, making it appear larger and more brilliant. One of the most popular engagement ring styles. Can add 0.3–0.5 ct of visual size without the cost of a larger center diamond. Learn more: Ring Settings Guide.

SHAPE A fancy shape diamond resembling a heart. Requires precise symmetry—any imbalance in the two lobes is immediately noticeable. Best viewed in larger sizes (1 ct+) where the shape is clearly defined. Learn more: Diamond Shapes Guide.

PRODUCTION One of the two main methods for growing lab diamonds. Replicates the intense pressure and heat of the earth's mantle. A diamond seed is placed in a chamber with carbon source material and subjected to extreme conditions (~1,500°C, 1.5 million PSI). Excellent for producing large, colorless diamonds. Compare: CVD.

CLARITY Second-highest clarity grade. No inclusions visible under 10× magnification, though minor surface blemishes may be present. Like FL, IF is a premium grade worth paying for only if you specifically want a "clean certificate." For practical wear, VS1 offers identical real-world appearance at a lower cost.

LAB The most widely used certification laboratory for lab-grown diamonds. Generally grades slightly more liberally than GIA—an IGI VS1 may be closer to a GIA VS2. This is why IGI-certified lab diamonds cost 20–40% less than GIA-certified stones with identical stated grades. Still reliable and widely accepted by retailers and insurers. See our comparison: IGI vs GIA.

CLARITY Internal imperfections within a diamond. Types include crystals, needles, clouds, feathers (fractures), pinpoints, and cavities. The position, size, and nature of inclusions determine a diamond's clarity grade. Inclusions near the center are more visible than those near the edge. Eye-clean inclusions don't affect beauty or durability.

A measure of gold purity, not to be confused with carat (diamond weight). 24 karat = pure gold (too soft for rings). 18k = 75% gold (most popular for fine jewelry, good durability). 14k = 58.3% gold (more durable, less expensive, slightly less yellow). 10k = 41.7% gold (durable, budget-friendly). Most engagement rings are 14k or 18k white, yellow, or rose gold, or platinum.

A diamond grown in a laboratory using either CVD or HPHT technology. Chemically, physically, and optically identical to a natural diamond—both are pure crystalline carbon. Lab diamonds are NOT simulants (like cubic zirconia or moissanite). They cost 60–80% less than natural diamonds of equivalent quality. See: Lab vs Natural Diamonds.

A microscopic identification number engraved on the diamond's girdle by a certification lab. This number matches the grading report, confirming authenticity and allowing the stone to be identified if lost or stolen. Always verify the inscription matches the certificate before accepting a diamond.

Describes how elongated or square a diamond looks. Calculated by dividing the longer dimension by the shorter. For oval cuts, 1.30–1.50 is most popular. For pear cuts, 1.45–1.75. Cushion cuts often look best at 1.00–1.05 (square) or 1.15–1.30 (rectangular). Personal preference is key—there's no universally "correct" ratio.

SHAPE An elongated shape with pointed ends (football/boat shape). Maximizes carat weight—appears significantly larger than a round of the same weight. Prone to the "bow-tie effect" (dark shadow across center). Choose carefully and inspect images. Learn more: Diamond Shapes Guide.

Small accent diamonds (typically under 0.2 ct each) used in pavé settings, halos, and side stones. Melee diamonds significantly affect a ring's overall brilliance and cost. High-quality melee should be well-matched in color and clarity for a consistent look.

A diamond simulant (not a diamond) made of silicon carbide. Much cheaper than lab diamonds, with higher fire/brilliance—sometimes described as "too sparkly" compared to a diamond. Moissanite is NOT the same as a lab-grown diamond; different chemical composition, different physical properties. See: Lab vs Natural guide.

A diamond formed naturally deep within the earth over billions of years under extreme heat and pressure. Chemically identical to a lab-grown diamond. Natural diamonds are scarce and command higher prices; their resale value is generally better than lab-grown diamonds. See the full comparison: Lab vs Natural Diamonds.

SHAPE An elongated brilliant-cut diamond. One of the most popular shapes for modern engagement rings—appears larger per carat than a round, flatters long, slender fingers, and generally costs 10–20% less than a round of the same weight. Watch for the "bow-tie effect." Learn more: Diamond Shapes Guide.

SETTING Small diamonds set closely together along the ring band, held in place by tiny metal beads (prongs). Creates a "paved with diamonds" look, adding significant brilliance. Micro-pavé uses even smaller stones for a more delicate appearance. Learn more: Ring Settings Guide.

ANATOMY The lower portion of a diamond below the girdle. Pavilion angle is critical to light performance—it determines how light reflects back up through the table. Too steep or too shallow causes light to "leak," reducing brilliance.

SHAPE A hybrid of round and marquise—rounded at one end, pointed at the other. Highly flattering when worn with the point toward the fingertip. Elongates the finger and appears larger than a round of the same weight. Ideal length-to-width ratio: 1.45–1.75. Learn more: Diamond Shapes Guide.

METAL A dense, white precious metal used for engagement ring bands. Naturally white (doesn't need rhodium plating like white gold), hypoallergenic, and extremely durable. More expensive than gold, and heavier. Platinum is 95% pure (Pt950) for fine jewelry. Scratches develop a patina that many people find desirable.

CUT A grade on a diamond's grading report indicating the quality of its surface finish. Graded: Excellent → Very Good → Good → Fair → Poor. Aim for Excellent or Very Good. Poor polish results in microscopic surface defects that reduce brilliance.

SHAPE A square brilliant-cut diamond with sharp, uncut corners. The second most popular shape after round. Exceptional brilliance, modern aesthetic, and lower price than round (better rough diamond usage). The pointed corners are vulnerable to chipping—use a 4-prong setting that covers the corners. Learn more: Diamond Shapes Guide.

SETTING The most common engagement ring setting, using metal tines (prongs/claws) to hold the diamond. Allows maximum light into the stone. Available in 4-prong or 6-prong (6-prong more secure; 4-prong allows more light). Check prong tightness annually. Learn more: Ring Settings Guide.

SHAPE A rectangular or square brilliant-cut diamond with cropped corners. Combines the elegance of an emerald's outline with the brilliance of a round. Excellent at hiding inclusions and color. Popular choice for those who love the rectangular shape but want maximum sparkle. Learn more: Diamond Shapes Guide.

Lab-grown diamonds generally have lower resale value than natural diamonds due to falling production costs. This is a known trade-off, not a scandal—most couples buy engagement rings to wear, not as investments. If resale value is important to you, consider a natural diamond or understand that you're paying for the sentiment, not the asset. See: Lab vs Natural.

SHAPE The most popular diamond shape, accounting for ~60% of all engagement ring diamonds. 57 or 58 precisely engineered facets maximize brilliance. The "ideal cut" proportions are well-defined, making it easier to evaluate quality. Typically priced 10–20% higher than equivalent fancy shapes. Learn more: Diamond Shapes Guide.

OPTICS The flashes of light and dark seen as a diamond moves. The "sparkle" you see when a diamond catches light. Alongside brilliance and fire, it's the third element of a diamond's visual appearance. High-quality cut maximizes scintillation by optimizing facet size and placement.

CLARITY Inclusions visible under 10× magnification and potentially visible to the naked eye (especially SI2). SI1 is often eye-clean; SI2 is a gamble—always inspect HD images or 360° video before buying SI2. Great value tier for lab-grown diamonds where the savings are significant. See our full guide: 4Cs Guide.

SETTING An engagement ring with a single center diamond and no side stones. The most classic and timeless ring style—lets the center diamond take center stage. Available with prong, bezel, or tension settings. Learn more: Ring Settings Guide.

CUT A grade on a diamond's certificate measuring how precisely the facets are aligned and shaped. Graded: Excellent → Very Good → Good → Fair → Poor. Along with polish, symmetry forms part of the overall "finish" grade. Aim for Excellent or Very Good symmetry for maximum light performance.

ANATOMY The large, flat facet on the top of a diamond. The table percentage is the width of the table expressed as a percentage of the diamond's total width. For round brilliants, ideal table percentage is typically 54–60%. A very large table reduces fire; a very small one reduces brilliance.

SETTING A modern setting where the center diamond appears to "float" between two metal arms of the shank, held in place by the tension of the metal. Visually dramatic and minimalist. Less secure than prong or bezel settings—not ideal for very active lifestyles. Usually non-resizable. Learn more: Ring Settings Guide.

SETTING A ring with a center diamond flanked by two side stones, representing the past, present, and future. Side stones are usually matching shapes (oval flanking oval, round flanking round) or complementary (trapezoids, half-moons). Increases total diamond weight—and total brilliance—significantly. Learn more: Ring Settings Guide.

CLARITY Inclusions are minor and difficult to see under 10× magnification. VS1 and VS2 diamonds are essentially always eye-clean. For lab-grown diamonds, VS2 is widely considered the value sweet spot—indistinguishable from FL in real-world wear, at a significantly lower price. See our full guide: 4Cs Guide.

CLARITY Inclusions are extremely difficult to see, even under 10× magnification—only expert graders can find them. Virtually flawless in appearance. For lab-grown diamonds, VVS grades carry a price premium that is rarely justified for everyday wear. VS1–VS2 is almost always the better value choice. See: 4Cs Guide.

METAL Yellow gold alloyed with white metals (nickel, palladium, silver) and plated with rhodium to achieve a bright white finish. More affordable than platinum. Rhodium plating wears off over time (typically every 1–3 years) and requires replating (usually $50–$100). Ideal for buyers who want a platinum look at a lower price point.

METAL The classic, warm-toned ring metal. Available in 10k, 14k, and 18k. A key advantage: near-colorless diamonds (G–I) can appear whiter in yellow gold settings since the metal's warmth provides contrast. Yellow gold is hypoallergenic in higher karats and doesn't require rhodium plating.