Petra Letlapa Tala Collection

Type IIb blue diamonds special tender! 

Petra Diamonds Limited announces a special tender process for the Letlapa Tala Collection, being five blue diamonds of significant colour, clarity, size and heritage, all sourced from the famed Cullinan Mine in South Africa. Letlapa Tala means ‘blue rock’ in Northern Sotho (commonly known as Pedi), the predominant language spoken in the Cullinan area. 

The Letlapa Tala Collection consists of five Type IIb blue diamonds of 25.75, 21.25, 17.57, 11.42 and 9.61 carats in size. Type II diamonds contain no detectable nitrogen in their chemical structure and tend to display exceptional transparency. Type IIb stones contain a small amount of boron which is what determines their blue colour. 

Blue diamonds are so rare that most people working in the diamond industry have never even seen one. There are no official statistics on their recovery, so it is therefore even more unusual that these five spectacular stones were all recovered within the space of one week’s production in September 2020.

The Cullinan Mine is known as the world’s most important source of blue diamonds, as well as being the source of many other historic and magnificent stones, including the 3,106 carat Cullinan diamond which was cut to form the 530 carat Great Star of Africa and the 317 carat Second Star of Africa, being the two largest diamonds in the British Crown Jewels. 

The unique geology of the Cullinan kimberlite pipe means that the majority of its diamonds are aged between 3.2 and 1.1 billion years old – spanning a time in the Earth’s history from before the formation of the first major continents to the beginnings of multicellular life. 

However, Type IIb blue diamonds are so rare that their age has not been established. Recent studies on minerals trapped inside these diamonds imply that they are amongst the deepest-formed diamonds ever found, created at depths in excess of 500km below the Earth’s surface.  

The boron that gives their blue colour has been linked to seawater suggesting that these diamonds are a record of rocks from the ocean floor that have been transported to the lower mantle by plate tectonics, where these diamonds formed under conditions of extreme pressure and temperature. 

This is likely to be the first time that five blue rough diamonds have ever been offered for sale at one time, with buyers being offered the chance to bid either on individual stones, more than one, or for the entire collection.

The Letlapa Tala Collection will be available for viewings in the key diamond centres of:

1: Antwerp: 25 October – 1 November 2020

2: Hong Kong: 5 – 10 November 2020

3: New York: 16 – 20 November 2020

The sales tender for the collection will take place shortly thereafter and will close at 3pm GMT on 24 November 2020. Please note that all dates may be subject to slight change, based on the many factors to be managed logistically during the Covid-19 pandemic. Interested parties will be kept informed should there be any date changes.Appointments to view the collection can be made by contacting Group Head of Sales and Marketing at Petra.