Understanding the key factors when buying a diamond is essential to making a confident choice. In this guide, Benjamin Khordipour—author, lecturer, and celebrity jewelry expert—breaks down everything you need to know, with links to in-depth articles for each topic.
1. Diamond Cut
Diamond cut is one of the most important factors when determining a diamond’s beauty (and worth). It describes how well a diamond’s facets interact with light, directly impacting its sparkle and brilliance. An ideal cut will reflect light internally from one facet to another before returning it to the eye, creating a stunning, lively sparkle. Poorly cut diamonds, even if they are high in carat, color, or clarity, may look dull or lifeless. This is why understanding the quality of a diamond’s cut is essential when purchasing.
The cut grading system, ranging from Excellent to Poor, helps buyers evaluate the diamond’s light performance. Round diamonds are the only shape with a standardized cut grading, while fancy shapes (like emerald, oval, or princess) vary in cut quality based on design preference and light performance. The cut grade also influences the diamond’s durability, as poorly cut stones may be more prone to damage.
2. Diamond Color
Color is another critical aspect, with diamonds graded from D (colorless) to Z (light yellow or brown). Colorless diamonds are the most desirable and valuable, especially in traditional round shapes, which reveal more color than other shapes. However, slight tints may go unnoticed in certain shapes, allowing buyers to select lower grades that still look beautiful but cost less. Understanding the diamond’s color can help you balance appearance and value effectively.
While many opt for colorless diamonds, some shapes and settings allow for diamonds with a slight tint without compromising visual appeal. Yellow and rose gold settings, for instance, can make slightly tinted diamonds appear whiter. With fancy colored diamonds like pink, blue, or green, the intensity of the color greatly affects value and desirability.
Read the full article on diamond color.
3. Diamond Clarity
Clarity assesses the presence of natural imperfections within a diamond, called inclusions, and external flaws, called blemishes. These inclusions and blemishes can affect a diamond’s sparkle and are graded from Flawless (no visible inclusions or blemishes under 10x magnification) to Included (imperfections visible to the naked eye). While flawless diamonds are rare and valuable, many inclusions are so small that they don’t impact a diamond’s appearance without magnification.
Inclusions are often microscopic, so diamonds with lower clarity grades, such as VS (Very Slightly Included) or SI (Slightly Included), can still appear flawless to the naked eye. This allows buyers to get a beautiful diamond without paying the premium of flawless grades. Additionally, certain shapes, like emerald and Asscher cuts, reveal clarity more visibly due to their large open facets, while round and brilliant cuts hide imperfections more easily.
Read the full article on diamond clarity.
4. Diamond Carat Weight
Carat weight refers to a diamond’s size, with one carat equaling 200 milligrams. Generally, the larger the carat weight, the rarer and more expensive the diamond. However, carat weight doesn’t solely determine a diamond’s visual size, as the cut and shape also affect perceived size. For instance, well-cut, shallower diamonds can appear larger than poorly cut, deeper diamonds of the same carat weight.
Balancing carat weight with the other Cs can often provide a more beautiful diamond than focusing solely on size. A slightly smaller, well-cut diamond can offer excellent sparkle and be more visually appealing than a larger, poorly cut stone. Many buyers choose to prioritize cut, color, and clarity for the best balance of size and quality.
Read the full article on diamond carat weight.
5. Diamond Shape
Shape is the overall form of a diamond, with popular choices like round, princess, oval, and cushion. Each shape has unique qualities and appeals to different styles and preferences. Round diamonds are the most brilliant, thanks to their symmetrical faceting pattern, while fancy shapes like emerald and pear cuts offer distinctive looks and often appear larger for their carat weight.
The shape of a diamond also affects its setting compatibility, as some settings highlight certain shapes better than others. For instance, an oval or pear shape works well in solitaire settings that emphasize the diamond’s elongated form, while a cushion or radiant cut may suit halo settings that enhance sparkle. Selecting a shape involves considering personal taste, style, and how the diamond will complement its intended setting.
Read the full article on diamond shapes.
6. Diamond Certification
Certification is a crucial factor in ensuring that the diamond meets high-quality standards. A certificate from a reputable laboratory, such as the GIA, UGL or AGS, verifies the diamond’s characteristics, including carat weight, color, clarity, and cut. This report serves as an unbiased assessment and provides confidence in the authenticity and quality of the stone, especially when making a significant investment.
Certified diamonds come with a report number and detailed information that helps buyers make informed comparisons. Non-certified diamonds may come at a lower price, but they carry greater risk, as the actual quality may not match the stated details. A certification also assists in valuing the diamond for resale or insurance purposes.
Read the full article on diamond certification.
7. Diamond Fluorescence
Fluorescence refers to a diamond’s reaction to ultraviolet light, which can make the stone appear blue in certain lighting conditions. While fluorescence is often invisible in regular lighting, it can influence the diamond’s appearance in sunlight or under UV lights. Strong fluorescence may make a diamond look hazy, while faint or medium fluorescence can enhance color in some diamonds.
Many buyers find that faint or medium fluorescence adds charm, especially in lower color grades, as it can make slightly yellow diamonds appear whiter. However, high fluorescence may affect transparency, so it’s essential to view a diamond in multiple lighting conditions to understand its full effect.
Read the full article on diamond fluorescence.
8. Diamond Resale Value and Investment
While many view diamonds as investments, resale value varies depending on factors like cut, color, clarity, and carat weight, as well as market demand. Certain diamonds, especially high-quality natural stones, may retain or increase their value over time, while others may depreciate. The rarity of antique and high-carat diamonds often enhances their resale potential.
Lab-grown diamonds generally do not hold value as well as natural diamonds due to their abundance and lower rarity. Buyers should consider whether they are purchasing primarily for beauty or as a potential asset, as this can influence the ideal type and quality of diamond to choose.
Read the full article on diamond resale value and investment.
9. Ethical Sourcing and Conflict-Free Diamonds
Ethical sourcing ensures that a diamond is mined and traded without funding conflict or unethical labor practices. Conflict-free diamonds are certified through processes like the Kimberley Process, which helps prevent the sale of diamonds from conflict zones. Many buyers today prioritize ethically sourced diamonds to align with their values.
Some jewelers offer additional certifications for environmental responsibility, tracing each diamond from its origin to the final sale. This focus on ethical sourcing provides transparency and peace of mind for consumers concerned about their purchase’s social and environmental impact.
10. Colored Diamonds
Colored diamonds, known as “fancy diamonds,” range in hues from pink, blue, and green to yellow, purple, and beyond. Unlike traditional white diamonds, these diamonds are valued based on the intensity and purity of their color rather than colorlessness. The richer and more vibrant the color, the more rare and valuable the diamond is. Colored diamonds are graded on a scale that includes descriptors like Faint, Fancy Light, Fancy, Fancy Intense, and Fancy Vivid, each reflecting different levels of color saturation.
Colored diamonds are prized by collectors and often sought for their unique beauty and rarity. Naturally colored diamonds are rare, and lab-grown colored diamonds offer a more affordable alternative. When choosing a colored diamond, it’s essential to consider the hue, tone, and saturation to find a stone that fits personal style and investment goals.
Read the full article on colored diamonds.
11. Diamond Symmetry and Polish
Symmetry and polish describe the precision of a diamond’s cut, impacting its sparkle and overall appearance. Symmetry refers to the alignment of a diamond’s facets, while polish assesses the surface quality. High symmetry and polish grades result in better light reflection and a smoother appearance.
These factors are graded individually, and higher grades contribute to a more brilliant diamond. Lower symmetry or polish grades may cause light leakage, reducing the diamond’s visual appeal.
12. Understanding Diamond Inclusions and Blemishes
Inclusions and blemishes are natural imperfections found in most diamonds. Inclusions are internal flaws, while blemishes occur on the diamond’s surface. Both factors impact clarity grades, with higher grades having fewer visible imperfections.
Some inclusions are invisible without magnification, allowing buyers to choose diamonds with lower clarity grades that still look flawless to the naked eye. Understanding these characteristics helps in selecting a diamond that balances appearance with budget.
Diamond Brilliance and Sparkle
Brilliance and sparkle are determined by a diamond’s cut quality, which influences how it reflects and refracts light. High-quality cuts maximize the diamond’s ability to capture and return light, creating a dazzling effect. Cut, polish, and symmetry work together to achieve optimal brilliance.
While carat weight and color are essential, the sparkle often has the most visual impact, making a diamond appear lively and captivating. Prioritizing cut quality ensures the diamond looks stunning in various lighting conditions.
Popular Diamond Origins and Provenance
Diamond origins and provenance add historical and sentimental value, especially for antique or vintage diamonds. Famous sources like Botswana, Canada, and Russia are known for their high-quality stones and ethical mining practices.
Some buyers seek diamonds from specific regions for their unique characteristics or historical value. Knowing a diamond’s provenance can enhance its appeal and provide insight into its journey from mine to market.
Antique Diamonds vs. Modern Diamonds
Antique diamonds are cut using traditional methods, often with larger facets and a softer glow, while modern diamonds are precision-cut for maximum sparkle. Antique cuts, such as the Old European or cushion cut, are rare and appealing for vintage enthusiasts, offering a unique look compared to modern round brilliants.
Modern diamonds are typically more brilliant due to advanced cutting techniques, but antique diamonds possess distinct charm and history. Deciding between antique and modern diamonds depends on personal style and the desired aesthetic.
Read the full article on antique diamonds vs. modern diamonds.
Bow-Tie Effect in Diamonds
The bow-tie effect appears as a dark shape resembling a bow tie in certain diamond cuts, like ovals, marquises, and pears. This shadow results from light leakage caused by the diamond’s cut and can vary in visibility.
Some bow-ties are faint and do not detract from the diamond’s beauty, while others can be prominent and distracting. Understanding this effect helps buyers choose diamonds with optimal sparkle and minimal bow-tie shadows.
Read the full article on the bow-tie effect in diamonds.
Diamond Girdle
The girdle is the narrow band that encircles the widest part of the diamond, separating the crown from the pavilion. It can range from very thin to very thick, and its thickness affects the diamond’s durability and value.
A balanced girdle thickness ensures that the diamond is secure without compromising its beauty. Buyers can find the girdle thickness on certification reports to help choose a well-proportioned diamond.
Read the full article on diamond girdle.
Diamond Table and Depth
The table is the flat, topmost facet, while depth is the distance from the table to the culet at the bottom. Together, they impact a diamond’s light performance, with ideal proportions maximizing brilliance and fire.
Too shallow or deep a depth can result in a diamond looking smaller or less sparkly. Certification reports include these measurements, guiding buyers toward diamonds with optimal proportions.
Read the full article on diamond table and depth.
Diamond Insurance
Diamond insurance protects against loss, theft, or damage, providing peace of mind for valuable purchases. Policies may cover full replacement value or repairs, ensuring financial security if the unexpected occurs.
Insuring a diamond typically requires an appraisal and a certification report, which documents its value and characteristics. This safeguard is especially recommended for high-value or sentimental pieces.
Read the full article on diamond insurance.
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