The Cut Guide  ·  Reference Antique Brilliant · Cushion Family

Shape  ·  Face-Up View

Light Performance  ·  Live

Cut Reference  ·  No. 012

Old Mine
Cut

Antique Brilliant · 58 Facets · Cushion Outline

The oldest form of the modern brilliant — cut from the 17th century onward to follow the natural crystal, optimized for weight retention, and finished by hand under candlelight. The original diamond experience, unchanged.

The Old Mine cut predates the concept of optical optimization entirely. Cutters working in Brazil, India, and South Africa from the 1600s through the early 1900s shaped stones to preserve as much rough as possible — following the natural octahedral crystal form of the diamond rather than imposing an ideal geometry on it. The result is a cushion-shaped outline with a tiny table, a towering crown, and a dramatically large, open culet. No two Old Mine cuts are identical; the soft squared corners, slightly irregular girdle, and hand-polished facets are the fingerprints of the individual cutter. Under candlelight — the only light these stones were ever meant to be seen in — the fire is extraordinary. Under modern electric light, the brilliance is softer than a modern brilliant, but the character is incomparable.

Origin

The "old mine" name refers to the Brazilian and early South African mines that supplied diamonds to Europe from the 17th through 19th centuries — before the discovery of the Kimberley deposits in 1867 transformed the global supply. Virtually every important diamond in Georgian and early Victorian jewelry is an Old Mine cut: the stones in Napoleonic-era parures, the gems in the great Romanov jewels, the celebrated diamonds of the Indian trade. The style gave way to the Old European cut as mechanical bruting allowed a more consistent round girdle, and then to the modern brilliant in the 1920s. Authentic Old Mine cuts are found today in antique jewelry, estate sales, and a small number of specialist dealers. New "Old Mine inspired" cuts — sometimes called "antique cushion" — are being produced for buyers who want the aesthetic without the provenance.

On The Hand
Softening
The cushion outline of the Old Mine cut is universally flattering — the soft rounded corners add warmth without the sharpness of a princess or the strong elongation of an oval. The high crown gives the stone visible height, making it appear more three-dimensional than a modern cushion. Works beautifully with antique settings (Georgian collet, Victorian gallery) or stands alone in a simple modern bezel for deliberate contrast.
58
Facets
30–40%
Table %
Max Fire
Light Character
Irregular
Symmetry
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Old Mine Cut thecutguide.com
Specifications
Table Percentage
30 – 40%
The smallest table of any major brilliant family. This proportion drives the cut's extraordinary fire — and its relatively softer brilliance under electric light. It is not a deficiency; it is the design.
Crown Angle
42 – 48°
Steeper than even the OEC. The high crown creates the visual depth and the dramatic candlelight fire that defines antique diamonds. In profile, Old Mine cuts appear taller and more sculptural than modern stones.
L:W Ratio
1.00–1.10
Approximately square with soft, rounded corners. Ratios above 1.10 produce more rectangular Old Mine cuts — less common but not undesirable. The outline is always slightly irregular; this is hand-craftsmanship, not error.
GIA Grading
OMC Grade
The GIA report will read "Old Mine Cut." Anything labeled Old Mine Cut without a GIA report requires independent verification — the term is sometimes applied loosely to antique cushions that are not true OMCs.
Polish / Symmetry
VG / Fair+
Fair symmetry is normal and expected in authentic Old Mine cuts — they were cut by hand to a different standard. Evaluate symmetry visually rather than by grade. A GIA "Fair" on an OMC is not the same as a "Fair" on a modern round.
Light Performance
Brilliance70
Fire96
Scintillation72
Size per Carat74
Clarity Concealment85

Scores reflect performance under modern electric light. Under candlelight or warm ambient lighting — the environment for which this cut was designed — the fire and scintillation readings would climb significantly. The Old Mine cut is the most lighting-responsive cut family in gemology.

Budget
vs. Round Brilliant
−10% to +20%
Wide range depending on quality, condition, and provenance. Collector demand for authentic antique cuts has increased sharply. Fine OMCs — good color, VS clarity, well-preserved — routinely command premiums over modern rounds.
Lab-Grown OMC
−35 to −50%
Specialty cutters produce lab-grown antique cushions and OMC-inspired cuts intentionally. These are new stones cut to antique proportions — not authentic OMCs, but optically comparable. Legitimate for buyers who want the look without the provenance cost.
What Retailers Won't Tell You
⚠ "Antique Cushion" Is Not Always Old Mine
The terms are used interchangeably in retail, but they are not the same. A true Old Mine cut is a 17th–19th century stone, cut by hand, with a GIA report identifying it explicitly as "Old Mine Cut." Modern "antique cushion" cuts are new stones cut to antique-inspired proportions. Both can be beautiful — but they carry different price justifications, and paying Old Mine premium for a new antique cushion is paying for a narrative that isn't there.
⚠ Irregular Symmetry Is Not a Defect
Old Mine cuts will carry GIA symmetry grades of Fair or Good — sometimes Poor. This reflects the inevitable irregularity of hand-cutting against a standard developed for machine-cut modern stones. Do not apply modern symmetry standards to antique cuts. A GIA "Fair" on an OMC describes authentic antique character; the same grade on a modern round describes a problem. Evaluate the stone visually, not by the grade alone.
The Cut Guide  ·  Assessment  ·  Old Mine
"The Old Mine cut is the most historically significant diamond cut that survives in quantity. It predates optimization, predates electric light, and predates the assumption that a diamond should sparkle rather than glow. For buyers who want a stone with genuine historical provenance and the most extraordinary fire in any lighting condition, this is the cut — understanding that you are buying into an era, not a specification. There is no modern substitute for the experience of seeing an authentic Old Mine cut in candlelight."
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