In the intricate world of diamond grading, SB is an abbreviation that stands for Short Bezel. This term specifically refers to a symmetry characteristic identified during the detailed analysis of a diamond's cut.
Understanding Diamond Symmetry and Facets
A diamond's brilliance, fire, and scintillation are heavily influenced by its cut, which includes its proportions, polish, and symmetry. Symmetry refers to the precise alignment and evenness of a diamond's facets. Facets are the flat, polished surfaces on a diamond that allow light to enter, reflect, and exit the stone, creating its sparkle.
The bezel facets are eight kite-shaped facets located on the crown (top part) of the diamond, extending from the girdle (the diamond's widest point) towards the table (the flat top surface). They play a crucial role in the diamond's light performance.
SB: Short Bezel Explained
When a grading laboratory notes SB or Short Bezel on a diamond's report, it indicates that one or more of these bezel facets are shorter than ideal or expected. This is a minor symmetry variation, often microscopic, identified by expert graders using precise tools.
Such a variation means the facet's length deviates from the optimal proportions, potentially affecting the overall symmetry of the diamond's crown. While often subtle, these details contribute to the overall symmetry grade a diamond receives.
Common Diamond Symmetry Abbreviations
Gemological laboratories use a range of abbreviations to denote specific symmetry characteristics observed during grading. Understanding these terms can provide deeper insight into a diamond's craftsmanship. Here are a few common ones:
| Abbreviation | Meaning |
|---|---|
| SB | Short Bezel |
| SM | Short Main |
| SPV | Star Percentage Variation |
| SV | Star Angle Variation |
These abbreviations are typically found in the "Comments" section or within the "Symmetry" section of a diamond grading report, providing specific details that contribute to the diamond's final symmetry grade (e.g., Excellent, Very Good, Good, Fair, Poor).
Impact on Diamond Grade and Appearance
A "Short Bezel" characteristic is typically a minor detail that, on its own, might not significantly impact a diamond's overall appearance to the naked eye. However, it contributes to the overall assessment of the diamond's symmetry.
- Symmetry Grade: While a single "SB" might still allow a diamond to achieve an "Excellent" or "Very Good" symmetry grade, multiple or more pronounced symmetry deviations could lower the grade.
- Light Performance: In most cases, a minor "Short Bezel" would have negligible impact on a diamond's brilliance or fire. However, significant or numerous symmetry issues can subtly affect how light travels through the diamond, potentially reducing its sparkle.
- Value: Diamonds with higher symmetry grades generally command higher prices due to their superior craftsmanship and aesthetic appeal.
Why Understanding SB Matters
For diamond buyers, understanding abbreviations like SB provides valuable context when reviewing a diamond grading report. It allows for a more informed decision by recognizing that even highly graded diamonds may have minor, almost imperceptible characteristics. Focus should always be placed on the overall symmetry grade and how it contributes to the diamond's beauty and sparkle, rather than getting fixated on every minor detail if the overall grade is high.
