OREANDA-NEWS. Petra Diamonds Limited announces the recovery of a 23.16 carat pink diamond of exceptional colour and clarity from the Williamson mine in Tanzania. 

The stone is an example of the high quality pink diamonds for which Williamson is known and is the most significant recovery by Petra from the mine to date.  Pink diamonds are only found in a handful of mines throughout the world and their rarity ensures that they are one of the most highly coveted of all the fancy colours. 

The diamond will now be offered for sale by appointment in Antwerp as part of Petra's December tender process.

About Petra Diamonds Limited

Petra Diamonds is a leading independent diamond mining group and an increasingly important supplier of rough diamonds to the international market. The Company has interests in five producing mines: four in South Africa (Finsch, Cullinan, Koffiefontein and Kimberley Underground) and one in Tanzania (Williamson). It also maintains an exploration programme in Botswana. 

Petra has a core objective to steadily increase annual production to ca. 5 million carats by FY 2019. The Group has a significant resource base of ca. 300 million carats. 

Petra conducts all operations according to the highest ethical standards and will only operate in countries which are members of the Kimberley Process. Petra is quoted with a premium listing on the Main Market of the London Stock Exchange under the ticker 'PDL' and is a member of the FTSE 250. F

About the Williamson mine

Located in the Shinyanga Province in Tanzania, Williamson is the country's only important diamond producer. The mine is an open pit operation based upon the 146 hectare Mwadui kimberlite pipe, which is the world's largest economic kimberlite by surface area.  Despite having been in continuous operation since 1940, the pit is only 95 metres at its deepest point due to the significant size of the deposit. 

Williamson produces high quality diamonds, as evidenced by the average value of US$298 per carat in FY 2015, and is renowned for beautifully rounded 'Type II' white goods and 'bubblegum' pink stones. The 'Williamson Pink', which is considered to be one of the finest pink diamonds ever recovered, was found at Williamson in October 1947, weighing 54 carats in the rough. The mine, then owned by the Canadian geologist and royalist Dr John Williamson, gave the diamond to Princess Elizabeth in 1947 as a wedding present. It was cut into a 23 carat round brilliant and set as the centre of a brooch in the form of a jonquil flower, designed and set by Cartier in 1953.

About Pink Diamonds

The pink colour in diamonds is thought to be brought about by an alteration to the stone's molecular structure, possibly caused by some kind of seismic shock at the time of the diamond's formation. Scientists speculate that this led to an atomic-level lattice defect that can selectively absorb light in the visible region of the spectrum. This colour centre is often concentrated in parallel planes (i.e. graining) within an otherwise nearly colourless diamond.