The Lesotho I is the largest of eighteen polished diamonds cut from the 601-carat Lesotho Brown rough recovered at the Letseng-La-Terae area of Lesotho in 1967, and is one of the historically significant diamonds of the modern era of African mining. The polished stone weighs 71.73 carats and is cut as a marquise (also recorded as a navette) brilliant.

The rough

The Lesotho Brown was found on 19 May 1967 by a Mosotho washwoman, Ernestine Ramaboa, who recovered it from a tributary of the Senqu (Orange) River near the Letseng-La-Terae area. At 601.25 carats it was the largest gem diamond found in Lesotho up to that date, and despite its name it was a near-colourless stone with a faint brown overtone - effectively top-cape colour rather than a true fancy brown by modern standards. The stone was sold by sealed-bid tender in Maseru in 1968 to Harry Winston for a reported U.S. $302,400, then a record price for a rough diamond of that size from the southern African region.

Cutting programme

Harry Winston's New York atelier cut the rough between 1968 and 1969 into eighteen polished diamonds, ranging in weight from less than one carat to the 71.73-carat Lesotho I. The cutting programme was directed by Winston's master cutters and proceeded conservatively to maximise total polished yield from a stone with significant included material. The eighteen stones bore Roman-numeral designations Lesotho I through Lesotho XVIII; Lesotho II at 60.61 carats was an emerald cut, and Lesotho III at 40.42 carats - a marquise - became famous in 1968 when Aristotle Onassis purchased it as the engagement ring for Jacqueline Kennedy, two months before their marriage.

Lesotho I in particular

The Lesotho I, at 71.73 carats marquise, is a D- to E-colour stone of high clarity and was the centrepiece of the Winston cutting programme. It was sold by Winston to a private collector and has changed hands several times over subsequent decades, including a documented appearance in the U.S. estate market in the 1990s. The stone is not in any public museum collection and current ownership is private. Like the rest of the Lesotho cutting series, it carries the provenance of having been cut from one of the most historically important Lesotho rough diamonds.

The Lesotho I, II and III together established the reputation of the Letseng area as a source of exceptional Type IIa goods, two decades before the modern Letseng mine entered industrial production in the late 1970s and again in the 2003 Gem Diamonds reopening. The 1967 Lesotho Brown discovery is now considered the founding event of the Lesotho diamond industry as recognised in the modern trade.