BijanDiamonds.com Dictionary
Old Mine Cut:
The old mine cut was a predecessor of the round brilliant cut. It came into existence in the late 17th century. The old miner was the first diamond cut that had all the facets of the present round brilliant cut: the bezel, the star, pavilion mains, etc. However, the facet alignment and sizes were in a different manner as compared to the current round brilliant. The old miner was also more of a square or cushion cut, rather than being round. In fact, today's cushion cut is an improved old mine cut