On Novem­ber 19, 2008, Sotheby’s in Geneva will be auc­tion­ing off a trio of gems that will pull at your patri­otic heart­strings. This mod­i­fied fancy red dia­mond of 1.92 carats (red dia­monds are sel­dom, if ever, more than a sin­gle carat, and are prob­a­bly the rarest found in col­ored dia­monds) is esti­mated to be sold at $2.5 to 3 million.

The Lesotho rough, a 601-carat dia­mond in its nat­ural, uncut state, was the only dia­mond of sig­nif­i­cance dis­cov­ered by a woman, Ernes­tine Ram­aboa. It even­tu­ally found its way to Harry Win­ston, whose sixth sense for gems was a divin­ing rod for dis­cov­er­ing the most spec­tac­u­lar rocks in the world. The Lesotho rough was cleaved (cut) into eigh­teen stones of vary­ing weights and sizes. The gem below is the Lesotho I (Lesotho III, a 40.42-carat marquise-shaped dia­mond, was given to Jacque­line Kennedy by Aris­to­tle Onais­sis on the occa­sion of their engage­ment). This gem boasts 71.73-carats and was the largest stone cut from the orig­i­nal rough. Until now, it has remained with the same owner since Harry Win­ston sold it. It is esti­mated at $3–5 million.

This flaw­less, fancy deep blue brio­lette, 10.48-carats and esti­mated at $6–9 mil­lion, makes you won­der how nature cre­ates such amaz­ing palettes. The blue in a blue dia­mond comes from the replace­ment of car­bon, com­monly found in the crys­tal for­ma­tion of dia­monds, with boron; this in turn affects how light is absorbed within the stone. In con­trast, a red dia­mond results from nitro­gen found in the crys­tal formation.