Old Mine Cut

What defines the cut

Old Mine Cut is the name given to hand-cut, cushion-outlined brilliants produced roughly through the Georgian and Victorian eras, before diamond cutting was mechanised and before Tolkowsky-era proportioning existed. Because each stone was cut and polished by hand against oil lamps or candlelight rather than optimised mathematically, old mine cuts vary considerably from stone to stone — squarer or more rounded, higher or lower crowns, larger or smaller culets — in a way that modern, machine-guided brilliants don't.

Visual characteristics

Old mine cuts typically show broader, warmer flashes of light than a modern round brilliant, with less of the small, scattered sparkle a modern cut produces — a look often described in the trade as having more "character" and less mechanical uniformity. A visible culet (the small flat facet at the very bottom, which modern cuts usually eliminate or minimise) is common and generally considered an authentic period feature rather than a flaw.

History

The name "old mine" refers to the source of the rough — historically Brazilian and, later, early South African ("old mine") production, as distinct from later "new mine" sources. It describes the cutting style of that era, not a literal mine of origin for any individual stone sold today.

Buying considerations

• Do not judge an old mine cut against modern brilliant symmetry standards — hand-cut asymmetry is normal and expected, not a defect.
• Look at overall light return and character rather than searching for the precision of a modern Excellent-cut round.
• Antique stones often have delicate, thin girdles from the period's tools — a small chip or two along the girdle is common on a genuinely antique stone and not necessarily a red flag, though it's worth having examined.
• Consider whether you like the look of a visible culet, since it's part of the authentic period aesthetic rather than something to avoid.

Modern reproductions

"Old mine cut" stones are also cut new today, deliberately reproducing the antique style for period-inspired jewellery. These aren't antique diamonds, just cut in the antique style — worth confirming which you're being offered, since genuinely antique stones and modern reproductions of the style can carry different value and character.

Jewellery suitability

Old mine cuts are the natural choice for genuinely antique or period-reproduction jewellery — Georgian and Victorian settings were designed around this cut's proportions and light behaviour, and a modern round brilliant looks visibly out of place in them.

Certification note

Labs frequently describe old mine cuts on certificates using broad terms like "modified cushion brilliant" or "cushion cut" rather than "old mine cut" specifically, since it isn't always a distinct formal grading category. The trade name a dealer uses may therefore differ from the exact wording on the certificate — worth checking both.