Old Mine Cut Diamond
The Old Mine cut was one of the older "antique" diamond cuts. It is somewhat reminiscent of the modern Cushion Cut in that it is somewhat square - "cushion shaped" - when viewed from the crown. Old mine cut diamonds were more "stubby" or "lumpy" in appearance than modern cuts, with very high crowns and deep pavilions. The Old Mine Cut had a much smaller table than is typical of modern diamonds, and a much larger culet.
Nowadays, antique cuts such as the Old Mine Cut have been superseded by modern diamond cutting - and the Old Mine Cut is not commonly performed, except perhaps when an authentic replacement stone is sought for an item of antique jewelry. As with other antique diamond shapes, original Old Mine Cut diamonds are now scarce and valuable to collectors because most were recut into modern brilliants. This recutting was typically performed for profit: Even though some of the stone's weight was lost, this was more than made up for by the increased value 'per carat'.
Old Mine Cut Diamond History
The Old Mine cut was also sometimes known as the Peruzzi Cut, Triple Cut Brilliant or Threefold Cut, and the stones are sometimes referred to affectionately as "Old Miners". The cut dates to 1681  and has been attributed to Vincent Peruzzi, a polisher from Venice who increased the number of facets in the crown of the Mazarin Cut (a.k.a."Double Cut Brilliant") from 17 to 33 - increasing the total number to 58.  This had the effect of significantly increasing the brilliance and fire of the stones in comparison to earlier cuts such as the Rose Cut. The Old Mine Cut stones, with their 58 facets, were the first to include all the facets now found in the modern brilliant.  They could be seen as direct ancestors of the modern brilliant - yet were still crudely cut by modern standards and are regarded as less "lively" than modern cut stones.
Modern diamond cuts have been optimized for their light refraction characteristics and the Old Mine Cut was performed before ideal cutting proportions, bruting, or high technology has evolved. Diamond cutting in old times was often performed with greater concern for retaining more of the original material than for optimization of light performance characteristics. For the above reasons, genuine antique old mine cut diamonds may have poor symmetry by modern standards - yet of course, as with all things antique, they have a charm of their own and there are those who find the "deep" shape very appealing.
The term "old mine cut" is a modern one. It first appeared in the early 20th century and the earliest mention of it I can find is from Frank Bertram Wade's 1916 "Diamonds: a study of the factors that govern their value". Wade's description of differences between the Rose Cut and the Old Mine Cut is interesting and worth quoting:
"The rose cut, which lent itself to the cutting of thin, broad pieces of diamonds, first had its day, and a well-made, rose-cut diamond, having a thickness of about one half the spread and with twenty-four triangular facets on it, is a fairly brilliant stone. Its colour-flashes, while scattering as compared to a well-made brilliant, are, nevertheless, very beautiful, and being usually direct spectra, rather than reflections of spectra, they are often more intense in colouring than many of the flashes from a brilliant. In fact, when the brilliant form was first introduced (the old, square, thick "old-mine cut"), many people of taste are said to have preferred the well made, rose-cut stones."
Similarly, the term "Peruzzi Cut" appears also to be a fairly modern invention - and the earliest reference to this term I can find is in the Gemological Institute of America's Gems & Gemology, Volume 5 from 1945. An Old French name for the Old Mine cut was the "Brilliant en trente-deux" - "The Brilliant in thirty-two", referring to the 32 crown facets (without the table). The old Mazarin Cut was referred to as the "Brilliant en seize" - "The Brilliant in sixteen."
The next stage in the 'evolution' of the diamond after the Old Mine Cut was the Old European Cut, which had a different facet pattern.
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