Symmetry refers to the precise alignment and intersection of a diamond’s facets. It is graded based on the presence of extra or misshapen facets, off-center culets and tables, and wavy girdles. In some cases, a diamond cutter may intentionally allow for a slight reduction in symmetry to prevent a defect in the rough stone from affecting the finished diamond. Symmetry is typically rated on a scale from poor to excellent.

While symmetry has a minor effect on the appearance of a diamond, it can significantly impact its price. Diamonds with excellent symmetry and polish are generally more expensive than those with good, fair, or poor symmetry, as they are considered more valuable. Diamonds with lower symmetry grades also have a higher likelihood of visible defects.