Asymmetry can appear in the outline, facet placement or girdle of an Old Mine Cut diamond. Judge the outline, facet placement and condition separately, then see whether the stone looks balanced face-up, stays coherent in motion and can be set safely.

What asymmetry can mean

Observation Possible cause Best check
Unequal corners or sides Original shaping, wear or repair Aligned image, measurements and loose-stone inspection
Off-centre table or culet Uneven facet placement or pavilion geometry Face-up view and full neutral-light rotation
Uneven light pattern Facet rhythm, tilt, obstruction or optical imbalance Matched video in diffuse, direct and room light
Irregular girdle Original handwork, natural, abrasion, chip or repolishing Magnification and a clock-position condition map

Use aligned photographs, movement and magnification to distinguish these features. The condition guide explains how to separate original features from damage.

Outline and facet symmetry are different

Outline symmetry concerns sides, corners and overall silhouette. Facet symmetry concerns placement and alignment, including the table and culet. Length-to-width ratio only describes proportion. Examine the face-up view for corner shape and culet position, then watch the pattern in motion.

GIA gives an overall cut grade only to standard round brilliants. Fancy shapes receive separate polish and symmetry assessments, so an Old Mine Cushion still needs visual and condition review.

Six outlines from current dossiers

These measurements show the range within the Old Mine Cushion family. Use the figures to compare squareness, elongation and face-up dimensions.

Public dossier Measurements L/W Use in comparison
10.05 Ct. D IF 12.25 × 12.40 × 8.31 mm 1.01 Near-square baseline at larger scale
8.01 Ct. H VVS2 11.72 × 11.60 × 7.14 mm 1.01 Near-square corner and side comparison
3.06 Ct. G VVS2 8.49 × 8.18 × 5.39 mm 1.04 Near-square footprint with movement video
2.13 Ct. D IF 7.74 × 6.52 × 4.68 mm 1.19 Moderately elongated outline
5.03 Ct. F VS1 11.72 × 8.91 × 6.16 mm 1.32 Elongated face-up comparison
5.16 Ct. G SI2 12.35 × 9.21 × 5.23 mm 1.34 Elongated comparison with different dimensions
Face-up view of a near-square 10.05 carat Old Mine Cushion diamond
10.05 Ct., ratio 1.01
Face-up view of a near-square 8.01 carat Old Mine Cushion diamond
8.01 Ct., ratio 1.01
Face-up view of a 3.06 carat Old Mine Cushion Brilliant diamond
3.06 Ct., ratio 1.04
Face-up view of a moderately elongated 2.13 carat Old Mine Cushion diamond
2.13 Ct., ratio 1.19
Face-up view of an elongated 5.03 carat Old Mine Cushion diamond
5.03 Ct., ratio 1.32
Face-up view of an elongated 5.16 carat Old Mine Cushion diamond
5.16 Ct., ratio 1.34

Use the gallery to compare outlines. Scale, orientation and lighting differ. A serious comparison needs equally scaled images and matched movement video.

When asymmetry works

It can work when the outline feels deliberate, the central pattern remains composed and contrast moves through the stone. It becomes a problem when it distracts, creates persistent darkness, complicates secure setting or signals damage.

Pay particular attention to thin girdle sections, surface-reaching features and weakened corners. Document these areas in the condition examination.

Rotation tells you more

Watch the outline, culet and contrast as the 3.06 Ct. diamond tilts. Follow each feature through a complete rotation.

Align the long axis vertically and watch a full rotation. Repeat while tracking the culet, corners and centre. Then turn the stone 90 degrees. If the impression changes mainly with orientation, the outline may be driving the reaction more than the facet pattern.

Set the actual outline

A custom setting can place prongs around the real corners, support a delicate girdle and leave clearance under a deep pavilion or culet. Ask for a face-up drawing traced from the measured outline.

Comparison checklist

  1. Match report, weight and measurements.
  2. Use the same scale, orientation, distance and light.
  3. Compare the outline separately from the facets.
  4. Track table, culet and contrast through movement.
  5. Inspect the loose girdle and map condition.
  6. Review support, prong positions and culet clearance.
  7. Separate personal shape preference from structural risk.

If alteration is being discussed, read Should You Recut or Preserve an Old Mine Cut? first.

Request a matched comparison

Ask for equally scaled face-up images, unedited rotation video, measurements, reports and condition notes. Request a private diamond search or ask about inspection.

Editorial attribution: Updated by Mort for Imperial Cushions from current dossier measurements and photography, 3 September 2026. Confirm the condition through loose-stone inspection.

Sources: GIA Guide to Old Mine Cut Diamonds; GIA Finish, Culet and Girdle Reference; GIA: How to Protect Your Diamond from Chipping.