Why Are Diamond Girdles Important?
The girdle plays a significant role in a diamond’s cut grade, ensuring the stone is securely set in jewelry. By minimizing damage risks during handling, the girdle proves crucial. Standard round diamonds showcase 16 “valley” and 16 “hill” positions, making the girdle rise and fall. Girdle thickness ranges from thick to thin and comes in variations: rough (unpolished), polished (unfaceted), or both polished and faceted. Nowadays, faceted and polished girdles are prevalent. Fancy shapes like Emerald and Asscher cuts, often feature polished but unfaceted girdles.
Girdle Scale
Girdles, much like other diamond attributes, undergo grading. By analyzing the center portion of a diamond through a profile view at 10x magnification, both the largest and smallest aspects of the girdle are assessed. Since girdles aren’t perfectly even, diamonds receive two grades. Here’s a breakdown of various girdle types:
Extremely Thin: Almost invisible, this girdle is prone to chipping or breaking and significantly affects the cut grade. Diamond depth tends to be shallow.
Very Thin: Careful setting is required to avoid chipping, and an excellent cut grade is unattainable. Diamond depth may also be shallow.
Medium: A well-proportioned girdle with minimal chipping risk, maintaining a favorable cut grade and diamond depth. Variations like thin-medium combinations are also common.
Slightly Thick: Nearly perfect, with minimal chipping risk and no adverse cut grade impact. Diamond depth remains optimal.
Thick: Slightly thicker than desired, possibly increasing diamond depth and typically resulting in a Very Good cut grade.
Very Thick: Excessively thick, often producing high depth and reducing the cut grade to Very Good or Good. Girdle reflections may appear within the diamond.
Extremely Thick: Disproportionately thick, potentially disrupting symmetry and reducing the cut grade to Good or Fair. This often results in a “fisheye” effect, diminishing the diamond’s sparkle.
How Is the Girdle Graded?
The girdle grade hinges on evaluating the thickest and thinnest sections. Using optical measuring devices or microscopes, measurements are taken and expressed as a percentage relative to the diamond’s average diameter. Visual inspection, from both a faceup and angled perspective, ultimately determines the final grade.
The Girdle’s Effect on a Diamond
The Ideal Girdle for Round Diamonds
In round cut diamonds, the girdle heavily influences the cut grade, necessitating careful attention. Fancy shapes, conversely, face lesser impact and fewer considerations. For round cut diamonds, a Medium-Slightly Thick girdle is ideal, ensuring perfect proportions and unobstructed sparkle. Fancy shapes generally accept a Thin-Thick range. However, drastically uneven girdles (e.g., Extremely Thin to Extremely Thick) disrupt symmetry, adversely affecting the diamond.
Why Very Small and Extremely Thick Girdles Are Not Favorable for Diamonds
Extremely thin girdles risk chipping during the setting process due to pressure and heat. Conversely, overly thick girdles trap excess carat weight at the diamond’s center, reducing its apparent size and brilliance with gray reflections. Fancy shapes, notably cushion cuts, often have thicker girdles, especially at corners. For step and princess cuts, thicker girdles might appear on one or two sides, preserving clarity and weight by reducing rough diamond loss. Grading accounts for the largest and smallest points of the girdle.
Notably, gemstones such as rubies, emeralds, and sapphires commonly exhibit very thick girdles.
Girdle Types
Unpolished Girdle: Rare in modern diamonds, these rough girdles are suboptimal for light performance.
Polished Girdle: Found mainly in step and princess cuts due to larger facet styles, making them acceptable for light optimization.
Faceted Girdle: The most recommended and popular among contemporary diamond cutters, faceted girdles enhance light performance and sparkle, representing the best girdle type available today.
FAQs
What is the girdle of a diamond?
The girdle of a diamond constitutes the outer edge separating the crown (top) from the pavilion (bottom). It’s the diamond’s widest part and where it is securely held in its setting.
Do all diamonds have girdle reflection?
Yes, girdle reflections are present in all diamonds, arising from the girdle’s role as the stone’s widest part. Light entering the diamond can reflect off the girdle, producing visible reflections, particularly from the side view. These reflections indicate natural diamond characteristics rather than damage or poor quality. The extent to which girdle reflections are noticeable depends on the diamond’s size, shape, polish, and lighting conditions.
How does the girdle affect a diamond?
The girdle’s influence on a diamond encompasses appearance, durability, and value:
1) Appearance: Girdle thickness affects a diamond’s perceived size; a thicker girdle makes it appear smaller, while a thinner girdle creates a larger appearance.
2) Durability: Thin girdles increase chipping or breaking risks, while thicker girdles enhance durability.
3) Value: Girdle dimensions impact a diamond’s value, with thicker girdles often preferred for their durability, whereas thin girdles can devalue the stone.
Overall, the girdle significantly factors into diamond quality assessments.
