Prepared by the Imperial Cushions editorial team. Laboratory terminology is retained where a report is cited; historical context and dealer judgment are identified as interpretation.
Read an old mine cushion as a complete arrangement of outline, crown, pavilion, table, culet and facets. The measurements help you connect its side profile with its face-up appearance.
Start with the outline
Study the corners, shoulders and sides before calculating anything. Length divided by width gives the ratio, but two stones with the same ratio can have very different silhouettes.
Compare dimensions with weight
Carat measures weight. Length and width show face-up spread. Depth may support a high crown or distinctive pavilion, or it may hide weight below the girdle. Compare antique cushions with stones of related shape and style.
Table and crown
A small table can accompany a high crown and broad crown facets. A larger table opens the central view. Read the table size alongside the crown and pavilion. Watch how brightness and contrast move through the table area.
Depth and pavilion
Total depth combines crown, girdle and pavilion. Use the side view to see how depth is distributed between those parts. Ask whether the stone has good face-up presence, a coherent profile and lively movement.
Culet and centre
An open culet is the small bottom facet visible through many antique stones. Check its size, position, condition and relationship to the central pattern. Slight displacement may suit the hand-cut character. A dominant culet may become the first and only thing the eye sees.
Girdle and symmetry
Map very thin or very thick sections around the full outline. Read the symmetry assessment beside the face-up view. Rotate the diamond and see whether any awkward corner or dead region keeps demanding attention.
Comparison worksheet
- Weight and millimetre dimensions.
- Length-to-width ratio.
- Table and total depth.
- Crown and pavilion profile.
- Culet size, position and condition.
- Girdle thickness by location.
- Brightness, contrast and fire in three lighting conditions.
- Setting implications.
Use the numbers to compare precisely, then look at the complete diamond. See real examples in the Antique Cushion Diamond Atlas or browse the current diamond dossiers.