Old Mine Cut Diamonds

Before the great diamond discoveries in South Africa in the 1870s, the world’s diamonds came from the old mines of India and, from the 1720s, Brazil, in the region of Minas Gerais. The stones cut from them in the eighteenth and nineteenth centuries came to be known as old mine cuts.

For a house with Brazilian roots, there is something special in that. Many of the diamonds worn in Georgian and Victorian Europe began their journey in Brazilian riverbeds.

Old mine cuts were shaped by hand and by eye, without the measuring instruments of modern cutting. The result is a softly squared outline with rounded corners, a high crown, a small table, a deep pavilion and, often, a large flat culet at the base that can be seen through the top as a small circle.

Their facets are broad and chunky, so instead of the fine, bright sparkle of a modern brilliant, they give big, slow flashes of light. They were designed to come alive in candlelight, and they still have a warmth and softness no modern cut quite matches. No two are the same.

The old European cut followed from the late nineteenth century: a round outline with similar chunky faceting, the bridge between the old mine and the modern round brilliant. The modern cushion is the old mine’s descendant, with the same soft outline but precise, computer-planned facets and far more brightness.

Genuine old mine cuts are increasingly scarce, because many were recut into modern shapes during the twentieth century. If you find one you love, look at it rather than its paperwork. There is no cut grade for antique cuts, so character and how the stone plays with light matter more than proportions.

Check the girdle and edges for chips, which are common in stones that have been worn for a century or more. Antique diamonds often sit in the lower colour grades, which suits their warm look, especially in yellow gold. An independent report will confirm what the stone is and note any treatment.

Today some cutters cut new diamonds, natural and lab-grown, in the old mine style, with the chunky facets and soft outline of the originals. They are not antique, and should never be described as such, but they offer the look with modern consistency and a wider choice of size and grade.

You can also carry the antique feeling through the setting: a bezel, a hand-engraved gallery, a slim yellow gold band, or a cluster in the Georgian manner.