Old mine cut is a trade name for an early cushion-shaped brilliant style. Common features include a softly squared outline, high crown, small table, deep pavilion, short lower-half facets and an open culet. Hand cutting gives each stone its own proportions.
The rough helped choose the shape
Before modern bruting, sawing and proportion systems, cutters worked more directly from the crystal. Preserving weight mattered, so finished stones could be square, elongated, off-centre or irregular.
Broad facets change the pace of light
Large facets can produce broad flashes of white light and fire with a different rhythm from the finer scintillation of many modern brilliants. The open culet may appear, change and disappear as the stone moves. Compare the measurements with this moving view.
Dating the diamond
Original old mine diamonds are associated with Georgian and Victorian jewellery, but cutters make old mine-inspired diamonds today. A grading report can describe the present cutting style. Age and provenance need separate evidence.
What to inspect
- Outline: does the asymmetry feel balanced face-up?
- Facet pattern: do broad reflections exchange light and dark in motion?
- Girdle: are there thin areas, chips, naturals or repairs?
- Spread: how do the millimetre dimensions compare with the weight?
- Lighting: what happens in diffused, direct and ordinary room light?
GIA's old mine cut guide covers the typical structure and condition points. Our guide to antique diamond light return shows how to read the pattern in motion.