Old Mine Cut Diamond — The Antique Cushion Brilliant
Old Mine Cut Diamond — The Antique Cushion Brilliant
A diamond fashioned in the cushion-shaped, hand-cut style of the Georgian and Victorian periods
An old mine cut diamond is a diamond fashioned in the old mine cut style — the cushion-outlined, hand-cut brilliant pattern that dominated the Georgian and Victorian periods, from approximately the late seventeenth century through the late nineteenth century. The phrase is sometimes used as a synonym for the cut itself, and sometimes specifically to refer to the diamond — the physical stone — fashioned in that style. The defining features are the cushion outline, the high crown, the small table, the open culet, and the handworked facet placement of pre-mechanised cutting practice. Most old mine cut diamonds in the contemporary trade are encountered in original Georgian or Victorian settings, with the loose-stone market making up a smaller but significant share.
Distinguishing features
An old mine cut diamond is most reliably identified by its outline — a cushion shape with rounded corners, distinct from the circular outline of an old European cut and from the geometric regularity of a modern cushion-modified brilliant. From the side, the crown is high (often 35 to 40 per cent of the total depth) and the pavilion is correspondingly compressed. The table is small relative to the girdle dimensions, and the culet is large and clearly visible as a flat octagonal disk through the table when the stone is viewed face-up. The 58-facet pattern is the standard brilliant pattern that was retained through the old European cut and the modern round brilliant.
Origin of the rough
Most old mine cut diamonds were fashioned from rough originating in the Indian diamond mines of Golconda and the Deccan plateau, or from the Brazilian deposits of Minas Gerais discovered in the early eighteenth century. South African production after the Kimberley discoveries of the late nineteenth century overlapped with the late period of old mine cutting; the cut was being progressively superseded by the rounded old European cut by the time South African rough became dominant. The provenance of the rough is rarely determinable from the cut diamond alone, but laboratory examination can sometimes infer Indian origin from low-nitrogen Type IIa material characteristic of Golconda production.
Optical character
Old mine cut diamonds produce broad, slow flashes of light and a characteristic chunky scintillation pattern that distinguishes them sharply from the rapid, fine scintillation of modern brilliants. Under candlelight or warm tungsten illumination — the lighting for which the cut was developed — old mine cuts exhibit a luminous, romantic character that many connoisseurs prefer to the more uniform brilliance of contemporary cuts. The cushion outline gives the stone a slightly less geometric, more organic visual presence than a round brilliant.
In the contemporary market
Loose old mine cut diamonds trade at the standard old-cut discount to modern brilliants of equivalent weight, colour, and clarity — typically 10 to 30 per cent — with the discount narrowing for well-cut examples and deepening for stones with conspicuous symmetry or condition issues. Old mine cuts in original Georgian or Victorian settings command the antique-jewellery premium and are valued as historic objects. The recent resurgence of interest in vintage and antique character has narrowed the loose-stone discount and increased prices on better old mine cut examples.
Care considerations
The open culet of an old mine cut diamond is slightly more vulnerable to chipping than the pointed culet of a modern brilliant. Original Georgian and Victorian settings — typically silver-on-gold for Georgian, gold-foiled or Victorian gold for the later period — also need careful handling and periodic professional inspection. Ultrasonic cleaning is acceptable for the diamond itself but may compromise foil-backed settings. We recommend gentle hand cleaning for foil-backed pieces and professional examination before any aggressive cleaning regime.