A large pinkish-brown diamond, the Star of the South has been a subject of attention and intrigue since its discovery in the mid-nineteenth century. Among the first Brazilian diamonds to receive international fame, it has made its way to Europe as well as India, where it was in the ownership of the royal Gaekwad family of the princely state of Baroda (in present-day Gujarat, India) for many years. In the wake of a number of anonymous sales and transfers from the late twentieth century onwards, the whereabouts of the Star of the South at the time of writing remain unknown.

The diamond was discovered in 1853 by Madi Magassa, an enslaved labourer, among the alluvial deposits of the Bagagem river in Minas Gerais, Brazil. She took the 261.38-carat rough diamond to the mine owner Casimiro de Moraes (referred to as Casimiro de Tal in some accounts). In keeping with the practice of rewarding honesty among enslaved workers, he released her from slavery and granted her a pension. Unaware of its value, de Moraes sold the diamond for GBP 3,000 to an unnamed purchaser, who took it to Rio de Janeiro and sold it for GBP 35,000. 

By 1855, it was in the possession of Parisian firm Halphen, who showcased the diamond at the Paris Industrial Exhibition that year, while it was still in the rough. Halphen also named it ‘Étoile du Sud’, French for ‘Star of the South’, referencing its South American origins. The diamond’s name later inspired the renaming of the city of its discovery to the Portuguese translation ‘Estrela do Sul’. Between 1856 and 1858, it was sent to Royal Coster Diamonds in Amsterdam, where it was cut by LB Voorzanger, who had also been responsible for re-faceting the Koh-i-Noor diamond shortly before.

Over three months, Voorzanger cushion-cut the diamond in an oblong form measuring 35 x 29 x 19 millimetres, reducing its weight to 128.48 carats but greatly enhancing its brilliance. The diamond continued to attract attention and grew in popularity through its media coverage, particularly after a replica of it was showcased at the International Exhibitions of London and Paris in 1862 and 1867 respectively. Later in the same decade, Halphen is said to have sent the Star of the South briefly to India, where it drew the attention of various members of royalty, including an unnamed maharaja who made an unsuccessful bid for the diamond. 

In the late 1860s, the Maharaja of Baroda Khande Rao II Gaekwad (r. 1856–70) bought the diamond for GBP 80,000 using the services of London dealer Edward Dresden, after whom the 78.5-carat English Dresden was named. The Gaekwad family later also purchased this diamond — which originated from the same region as the Star of the South — and in 1880, commissioned a necklace that would showcase both historic diamonds. In 1948, Khande Rao’s granddaughter-in-law the Maharani of Baroda Sita Devi (r. 1943–48) was photographed wearing this necklace by Henri Cartier-Bresson. While there is no conclusive information about the diamond between 1950 and 2001, the Gaekwad family claims that the Star of the South was included in its wealth tax returns until as late as 1988.

In 2001, an anonymous buyer bought the Star of the South and sent it to the Gübelin Gem Lab in Lucerne, Switzerland to be analysed, making it one of the few historic diamonds for which a comprehensive gemological analysis has been published. The luxury house Cartier is said to have purchased the Star of the South in 2002, according to reports that appeared in 2007.