Petra Diamonds: Difference between revisions
Reverted 2 edits by 217.138.134.134 (talk): Check your talk page for conflict of interest information and why I removed your edits. |
No edit summary Tags: Mobile edit Mobile web edit |
||
(18 intermediate revisions by 12 users not shown) | |||
Line 1: | Line 1: | ||
{{Short description|Jersey diamond mining company}} |
|||
⚫ | |||
{{Use dmy dates|date=April 2022}} |
|||
⚫ | |||
⚫ | |||
⚫ | |||
⚫ | |||
⚫ | |||
| logo_size = 200px |
| logo_size = 200px |
||
| type |
| type = [[Public company|Public]] |
||
| traded_as = {{LSE|PDL}} |
| traded_as = {{LSE|PDL}} |
||
| foundation |
| foundation = 1997 |
||
| location |
| location = [[Jersey]] |
||
| key_people |
| key_people = Peter Hill, [[Chair (official)|Chairman]]<br />Richard Duffy, [[Chief Executive Officer|CEO]] |
||
| industry |
| industry = [[Diamond mining]] |
||
| revenue |
| revenue ={{decrease}} US$325.3 million (2023)<ref name=results>{{cite web|url=https://wp-petra-diamonds-2023.s3.eu-west-2.amazonaws.com/media/2023/10/Petra-FY-2023-prelims-vfinal_15Sep2023_for-publishing.pdf |title=Preliminary Results Announcement for the Year ended 30 June 2023|publisher=Petra Diamonds|accessdate=15 February 2024}}</ref> |
||
| operating_income = US$ |
| operating_income ={{decrease}} US$20.3 million (2023)<ref name=results/> |
||
| net_income |
| net_income ={{decrease}} US$(102.4) million (2023)<ref name=results/> |
||
| products = Diamonds |
|||
| production = 3,700,000 carats (2016)<ref name=prelims/> |
|||
| production = |
|||
| homepage |
| homepage = [http://petradiamonds.com petradiamonds.com] |
||
}} |
}} |
||
'''Petra Diamonds''' Ltd is a diamond mining group headquartered in [[Jersey]]. |
'''Petra Diamonds''' Ltd is a diamond mining group headquartered in [[Jersey]]. Petra own one of the world's most productive mines historically, the [[Premier Mine|Cullinan Diamond Mine]] is famed for having produced the [[Cullinan Diamond|world's largest rough and polished diamond]]. The company is listed on the [[London Stock Exchange]]. |
||
|last=Janse |
|||
|first= AJA |
|||
|author-link= |
|||
|year=2007 |
|||
|title=Global Rough Diamond Production Since 1870 |
|||
|journal=Gems and Gemology |
|||
|volume=XLIII |
|||
|issue=Summer 2007 |
|||
|pages=98–119 |
|||
|publisher=GIA |
|||
|doi=10.5741/GEMS.43.2.98}}</ref> These mines include the [[Premier Mine|Cullinan Diamond Mine]] famed for having produced the [[Cullinan Diamond|world's largest rough and polished diamond]]. It is listed on the [[London Stock Exchange]]. |
|||
== History== |
== History== |
||
Line 38: | Line 30: | ||
=== South Africa === |
=== South Africa === |
||
Petra Diamonds operates three producing diamond mines in South Africa. These are all underground kimberlite pipe mines (Cullinan, Finsch and Koffiefontein).<ref>{{cite news|url=https://rapaport.com/analysis/petra-diamonds-sees-competitive-edge/|title=Where Petra Diamonds Sees Its Competitive Edge|date=24 October 2023|newspaper=Rapaport|access-date=6 February 2024}}</ref> |
|||
Petra Diamonds operates four producing diamond mines in South Africa. These are all underground kimberlite pipe mines (Cullinan, Finsch, Koffiefontein and Kimberley Underground). The company also had three smaller Fissure Mines (Helam, Sedibeng and Star), but Sedibeng and Star have recently closed and Helam is being run down for closure. Petra Diamonds has a record of turning De Beers' unprofitable South African mines into financial successes. According to [[Nicky Oppenheimer]], Chairman of De Beers, the reason for this was "De Beers was operating the mines with too large a cost structure, something Petra doesn't have."<ref name="miningmx.com">[http://www.miningmx.com/diamonds/554063.htm Petra buys De Beers' Kimberley mine for R78.5m] {{webarchive|url=https://web.archive.org/web/20081013151312/http://www.miningmx.com/diamonds/554063.htm |date=2008-10-13 }} Mining mx, 14 September 2007</ref> The underground kimberlite mines were purchased from De Beers Consolidated Mines.<ref>{{cite web|url=http://www.diamonds.net/Magazine/Article.aspx?ArticleID=32434&RDRIssueID=53|title=De Beers Sells Historic Mines|publisher=Diamonds|accessdate=18 October 2016}}</ref> |
|||
==== Finsch Mine ==== |
==== Finsch Mine ==== |
||
Line 52: | Line 44: | ||
The mine, previously known as Premier Diamond mine, is renowned for producing many of the world's largest and [[List of famous diamonds|most famous diamonds]], including the Cullinan Diamond, the world's largest gem diamond, at {{convert|3106|carat|kg}} rough. [[Sir Thomas Cullinan]], the former chairman of the Premier Diamond Mine, presented the Cullinan to England's King [[Edward VII]] in 1905.<ref>{{cite web|url=http://www.farlang.com/diamonds/williams_history_diamond_mines/page_437|title=Gemstones Diamonds Books - Farlang|work=Farlang|accessdate=1 April 2015}}</ref> The Great Star of Africa, which sits in the [[Sceptre with the Cross|Sceptre of the Crown Jewels]], was produced from the [[Cullinan Diamond]], and was until recently acknowledged to be the largest cut diamond in the world, weighing in at {{convert|530.20|carat|g}}. In 1985 it lost the record to the [[Golden Jubilee Diamond|Golden Jubilee]], which was found in the same mine as the Cullinan and weighed {{convert|545.67|carat|g}} in its polished state. More than a quarter of all diamonds weighing more than {{convert|400|carat|g}} have originated from Cullinan. It is also the world's only significant source of [[Diamond color|blue diamonds]]. One of these famous large blue diamonds was cut into several stones and made into a necklace which subsequently became known as the Cullinan Blue Diamond necklace.<ref>[http://www.gia.edu/loupeonline/29960/22166/2257/back_issue_detail.cfm Exploring Africa's Gem Trail] {{webarchive|url=https://web.archive.org/web/20060905130625/https://www.gia.edu/loupeonline/29960/22166/2257/back_issue_detail.cfm |date=2006-09-05 }} The Loupe GIA World News, Winter 2009</ref> |
The mine, previously known as Premier Diamond mine, is renowned for producing many of the world's largest and [[List of famous diamonds|most famous diamonds]], including the Cullinan Diamond, the world's largest gem diamond, at {{convert|3106|carat|kg}} rough. [[Sir Thomas Cullinan]], the former chairman of the Premier Diamond Mine, presented the Cullinan to England's King [[Edward VII]] in 1905.<ref>{{cite web|url=http://www.farlang.com/diamonds/williams_history_diamond_mines/page_437|title=Gemstones Diamonds Books - Farlang|work=Farlang|accessdate=1 April 2015}}</ref> The Great Star of Africa, which sits in the [[Sceptre with the Cross|Sceptre of the Crown Jewels]], was produced from the [[Cullinan Diamond]], and was until recently acknowledged to be the largest cut diamond in the world, weighing in at {{convert|530.20|carat|g}}. In 1985 it lost the record to the [[Golden Jubilee Diamond|Golden Jubilee]], which was found in the same mine as the Cullinan and weighed {{convert|545.67|carat|g}} in its polished state. More than a quarter of all diamonds weighing more than {{convert|400|carat|g}} have originated from Cullinan. It is also the world's only significant source of [[Diamond color|blue diamonds]]. One of these famous large blue diamonds was cut into several stones and made into a necklace which subsequently became known as the Cullinan Blue Diamond necklace.<ref>[http://www.gia.edu/loupeonline/29960/22166/2257/back_issue_detail.cfm Exploring Africa's Gem Trail] {{webarchive|url=https://web.archive.org/web/20060905130625/https://www.gia.edu/loupeonline/29960/22166/2257/back_issue_detail.cfm |date=2006-09-05 }} The Loupe GIA World News, Winter 2009</ref> |
||
The Cullinan mine continues to produce large stones. The Cullinan Heritage, a {{convert|507|carat|g|adj=on}} white diamond, was discovered in September 2009. This stone was the 19th biggest [[uncut diamond]] ever found and was sold in February 2010 to [[Chow Tai Fook Jewellery]] for $35.5m, the highest price ever paid for an uncut diamond.<ref>{{cite news| url=https://www.independent.co.uk/news/business/news/eggsized-diamond-sold-to-hong-kong-jeweller-for-a-record-35m-1912450.html | location=London | work=The Independent | title=Egg-sized diamond sold to Hong Kong jeweller for a record $35m | first=Alistair | last=Dawber | date=2010-02-27}}</ref> The previous record was held by [[Gem Diamonds]]' Leseli La Letšeng, which was bought for $18.4m by [[Graff Diamonds]] in December 2008.<ref>[https://www.telegraph.co.uk/finance/newsbysector/industry/mining/8395269/Gems-biggest-diamonds.html?image=3 Gem's biggest diamonds] The Telegraph</ref> |
The Cullinan mine continues to produce large stones. The Cullinan Heritage, a {{convert|507|carat|g|adj=on}} white diamond, was discovered in September 2009. This stone was the 19th biggest [[uncut diamond]] ever found and was sold in February 2010 to [[Chow Tai Fook Jewellery]] for $35.5m, the highest price ever paid for an uncut diamond.<ref>{{cite news| url=https://www.independent.co.uk/news/business/news/eggsized-diamond-sold-to-hong-kong-jeweller-for-a-record-35m-1912450.html |archive-url=https://ghostarchive.org/archive/20220526/https://www.independent.co.uk/news/business/news/eggsized-diamond-sold-to-hong-kong-jeweller-for-a-record-35m-1912450.html |archive-date=26 May 2022 |url-access=subscription |url-status=live | location=London | work=The Independent | title=Egg-sized diamond sold to Hong Kong jeweller for a record $35m | first=Alistair | last=Dawber | date=2010-02-27}}</ref> The previous record was held by [[Gem Diamonds]]' Leseli La Letšeng, which was bought for $18.4m by [[Graff Diamonds]] in December 2008.<ref>[https://www.telegraph.co.uk/finance/newsbysector/industry/mining/8395269/Gems-biggest-diamonds.html?image=3 Gem's biggest diamonds] The Telegraph</ref> |
||
==== Koffiefontein ==== |
==== Koffiefontein ==== |
||
Line 59: | Line 51: | ||
Diamonds were first discovered on the Koffiefontein farm in 1870. Mining started in the form of small claims that were later amalgamated into Koffiefontein Mine Limited. De Beers acquired control of Koffiefontein Mine Limited in 1911. Mining operations were then continuous until the advent of the Great Depression in 1932 when work was suspended. Between 1950 and 1953, a prospecting shaft was sunk which was followed by limited production. The mine was reopened in 1970 and preparations for increased production were completed in August 1971. Immediately after completing the preparations, production from the open pit commenced and proceeded to a depth of 270 metres. Underground development started in 1974 through a sampling programme. Underground production briefly took place in 1982 but ceased soon thereafter due to the 1981 slump in the diamond market. These operations were resumed in March 1987. During the period 1972 to the end of 2004, approximately 69.5 million tonnes of kimberlite ore were mined and 6.1 million carats of diamonds were recovered. In February 2006, De Beers ceased mining when the old order mining right for Koffiefontein expired and in July of that year Petra Diamonds commenced operating the mine under care and maintenance conditions. The acquisition of the mine was completed in July 2007 and Petra Diamonds was subsequently able to commence diamond recoveries by starting to process the stockpile through the plant.<ref>{{cite web|url=http://rough-polished.com/en/database/32876.html |title=Koffiefontein mine |publisher=Rough & Polished |accessdate=18 October 2016 |url-status=bot: unknown |archiveurl=https://web.archive.org/web/20130314193959/http://rough-polished.com/en/database/32876.html |archivedate=14 March 2013 }}</ref> |
Diamonds were first discovered on the Koffiefontein farm in 1870. Mining started in the form of small claims that were later amalgamated into Koffiefontein Mine Limited. De Beers acquired control of Koffiefontein Mine Limited in 1911. Mining operations were then continuous until the advent of the Great Depression in 1932 when work was suspended. Between 1950 and 1953, a prospecting shaft was sunk which was followed by limited production. The mine was reopened in 1970 and preparations for increased production were completed in August 1971. Immediately after completing the preparations, production from the open pit commenced and proceeded to a depth of 270 metres. Underground development started in 1974 through a sampling programme. Underground production briefly took place in 1982 but ceased soon thereafter due to the 1981 slump in the diamond market. These operations were resumed in March 1987. During the period 1972 to the end of 2004, approximately 69.5 million tonnes of kimberlite ore were mined and 6.1 million carats of diamonds were recovered. In February 2006, De Beers ceased mining when the old order mining right for Koffiefontein expired and in July of that year Petra Diamonds commenced operating the mine under care and maintenance conditions. The acquisition of the mine was completed in July 2007 and Petra Diamonds was subsequently able to commence diamond recoveries by starting to process the stockpile through the plant.<ref>{{cite web|url=http://rough-polished.com/en/database/32876.html |title=Koffiefontein mine |publisher=Rough & Polished |accessdate=18 October 2016 |url-status=bot: unknown |archiveurl=https://web.archive.org/web/20130314193959/http://rough-polished.com/en/database/32876.html |archivedate=14 March 2013 }}</ref> |
||
==== Kimberley Underground ==== |
|||
Kimberley Underground comprises three kimberlite pipe mines in close proximity: Bultfontein, Dutoitspan and Wesselton. These mines were integral to the economic development of South Africa as their output effectively financed development of the nascent gold industry. They are currently mining at depths of between 845 and 995 metres below surface. The mines have a history of producing large diamonds and fancy yellows, such as the [[Oppenheimer Diamond]] (253 carats rough). The largest diamond ever recovered at Kimberley Underground was +800 carats and the mine is also the source of the Kimberley Octahedral, at 616 carats, one of the largest uncut diamonds in the world.<ref>[http://www.internetstones.com/kimberley-octahedron-616-diamond-famous-jewelry.html Kimberley Octahedron Diamond] Internet Stones</ref> |
|||
The mines were closed by De Beers in August 2005 and subsequently Petra operated Kimberley Underground under care and maintenance from September 2007. Petra was given approval to operate the mines under De Beers’ licence and the acquisition completed in May 2010.<ref>[http://www.southafrica.info/business/investing/kimberleypetra-170907.htm#.UVWozBw72Ag Petra to reopen Kimberley mines] South Africa Info, 17 September 2007</ref> |
|||
==== Fissure Mines ==== |
|||
The Fissure Mines were acquired by Petra when it merged with Crown Diamonds NL in May 2005, introducing producing assets to what had previously been an exploration company.<ref>{{cite web|url=http://www.investegate.co.uk/petra-diamonds-ld/rns/proposed-merger-and-placing/200504260915015098L/|title=Proposed merger and placing|publisher=Investegate|accessdate=18 October 2016}}</ref> |
|||
=== Tanzania === |
=== Tanzania === |
||
Line 75: | Line 57: | ||
The Williamson Mine currently has a resource of 39.6 million carats (8,000 kg) (984 million tonnes of kimberlite). It has an average mining depth of 65 metres (90m at the deepest point) and a very low stripping ratio. Energy and Minerals Minister William Ngeleja said Petra's entry is "an opportunity to breathe new life into Williamson Mine and Tanzania's diamond mining sector."<ref>[http://www.diamondtopics.com/mixed-outlook-as-diamond-giant-de-beers-sells-williamson-mine-to-petra/ Mixed Outlook As Diamond Giant De Beers Sells Williamson Mine to Petra] All Africa, 16 September 2008</ref> |
The Williamson Mine currently has a resource of 39.6 million carats (8,000 kg) (984 million tonnes of kimberlite). It has an average mining depth of 65 metres (90m at the deepest point) and a very low stripping ratio. Energy and Minerals Minister William Ngeleja said Petra's entry is "an opportunity to breathe new life into Williamson Mine and Tanzania's diamond mining sector."<ref>[http://www.diamondtopics.com/mixed-outlook-as-diamond-giant-de-beers-sells-williamson-mine-to-petra/ Mixed Outlook As Diamond Giant De Beers Sells Williamson Mine to Petra] All Africa, 16 September 2008</ref> |
||
=== Botswana === |
|||
Petra commenced exploration in Botswana, following the acquisition of Kalahari Diamonds in September 2005. Petra Diamonds Botswana is the holder of approximately 21,519 km<sup>2</sup> of diamond exploration ground, all of which is "on craton" (the geological formation known to host diamonds). The company's current focus is on the KX36 kimberlite discovery, in the Kukuma East project area, and the potential for further discoveries in the area.<ref>[http://www.rough-polished.com/en/news/61408.html Drilling at Botswana’s Kimberlite KX36 shows strong micro diamond results - Petra] Rough & Polished, 15 March 2012</ref> |
|||
==See also== |
==See also== |
||
Line 96: | Line 74: | ||
[[Category:1997 establishments in Jersey]] |
[[Category:1997 establishments in Jersey]] |
||
[[Category:Companies listed on the London Stock Exchange]] |
[[Category:Companies listed on the London Stock Exchange]] |
||
[[Category:Companies in the FTSE SmallCap Index]] |
|||
[[Category:1997 initial public offerings]] |
[[Category:1997 initial public offerings]] |
Latest revision as of 14:08, 21 May 2024
Company type | Public |
---|---|
LSE: PDL | |
Industry | Diamond mining |
Founded | 1997 |
Headquarters | Jersey |
Key people | Peter Hill, Chairman Richard Duffy, CEO |
Products | Diamonds |
Revenue | US$325.3 million (2023)[1] |
US$20.3 million (2023)[1] | |
US$(102.4) million (2023)[1] | |
Website | petradiamonds.com |
Petra Diamonds Ltd is a diamond mining group headquartered in Jersey. Petra own one of the world's most productive mines historically, the Cullinan Diamond Mine is famed for having produced the world's largest rough and polished diamond. The company is listed on the London Stock Exchange.
History
[edit]Petra Diamonds was founded by Adonis Pouroulis in 1997 and was first listed on the Alternative Investment Market later that year.[2] It transferred to the Main Market in December 2011.[3]
Operations
[edit]Petra Diamonds' operations are focused in Africa:
South Africa
[edit]Petra Diamonds operates three producing diamond mines in South Africa. These are all underground kimberlite pipe mines (Cullinan, Finsch and Koffiefontein).[4]
Finsch Mine
[edit]Finsch diamond mine is one of the world's most important diamond mines and South Africa's second largest diamond operation by production. On 14 September 2011, Petra purchased Finsch as a fully staffed, operating mine from De Beers for a total consideration of ZAR1.4 billion. Finsch is a major producer, having supplied over 126 million carats in its 40 plus year life to date. Petra is currently implementing a development plan to lift production from ca. 1.4 million carats per annum to 1.9 million carats per annum by FY 2017 (involving both underground and tailings production).[5]
Cullinan Mine
[edit]In July 2008, Petra led a consortium which acquired the Cullinan diamond mine from De Beers Consolidated Mines for a total cash consideration of ZAR1 billion. In line with the South African Mining Charter, the Petra Diamonds Cullinan Consortium included broad based Black Economic Empowerment partners.[6]
The Cullinan kimberlite pipe is the second largest indicated diamond resource in the world by in-situ value. The current operating levels include the B-Cut at a depth of 747 metres, and beneath that lies the Centenary-Cut ("the C-Cut"), a world class diamond resource. The mine hosts a total resource of 202.1 million carats, including 16.5 million carats in tailings dumps.[7]
The mine, previously known as Premier Diamond mine, is renowned for producing many of the world's largest and most famous diamonds, including the Cullinan Diamond, the world's largest gem diamond, at 3,106 carats (0.6212 kg) rough. Sir Thomas Cullinan, the former chairman of the Premier Diamond Mine, presented the Cullinan to England's King Edward VII in 1905.[8] The Great Star of Africa, which sits in the Sceptre of the Crown Jewels, was produced from the Cullinan Diamond, and was until recently acknowledged to be the largest cut diamond in the world, weighing in at 530.20 carats (106.040 g). In 1985 it lost the record to the Golden Jubilee, which was found in the same mine as the Cullinan and weighed 545.67 carats (109.134 g) in its polished state. More than a quarter of all diamonds weighing more than 400 carats (80 g) have originated from Cullinan. It is also the world's only significant source of blue diamonds. One of these famous large blue diamonds was cut into several stones and made into a necklace which subsequently became known as the Cullinan Blue Diamond necklace.[9]
The Cullinan mine continues to produce large stones. The Cullinan Heritage, a 507-carat (101.4 g) white diamond, was discovered in September 2009. This stone was the 19th biggest uncut diamond ever found and was sold in February 2010 to Chow Tai Fook Jewellery for $35.5m, the highest price ever paid for an uncut diamond.[10] The previous record was held by Gem Diamonds' Leseli La Letšeng, which was bought for $18.4m by Graff Diamonds in December 2008.[11]
Koffiefontein
[edit]Koffiefontein mine is one of the world’s top diamond mines by average value per carat and produces exceptional white and coloured diamonds, a regular proportion of which are of between 5 and 30 carats. In 1994, a 232.34 carat diamond was recovered at Koffiefontein, being the largest rough diamond ever produced by the mine.[12]
Diamonds were first discovered on the Koffiefontein farm in 1870. Mining started in the form of small claims that were later amalgamated into Koffiefontein Mine Limited. De Beers acquired control of Koffiefontein Mine Limited in 1911. Mining operations were then continuous until the advent of the Great Depression in 1932 when work was suspended. Between 1950 and 1953, a prospecting shaft was sunk which was followed by limited production. The mine was reopened in 1970 and preparations for increased production were completed in August 1971. Immediately after completing the preparations, production from the open pit commenced and proceeded to a depth of 270 metres. Underground development started in 1974 through a sampling programme. Underground production briefly took place in 1982 but ceased soon thereafter due to the 1981 slump in the diamond market. These operations were resumed in March 1987. During the period 1972 to the end of 2004, approximately 69.5 million tonnes of kimberlite ore were mined and 6.1 million carats of diamonds were recovered. In February 2006, De Beers ceased mining when the old order mining right for Koffiefontein expired and in July of that year Petra Diamonds commenced operating the mine under care and maintenance conditions. The acquisition of the mine was completed in July 2007 and Petra Diamonds was subsequently able to commence diamond recoveries by starting to process the stockpile through the plant.[13]
Tanzania
[edit]Petra agreed to acquire the Williamson Mine in Tanzania in September 2008 from De Beers and completed the acquisition in February 2009.[14] The Williamson mine, which was discovered in 1940, has a reputation for the production of large, high value diamonds, with special stones (classified as larger than 10.8 carats (2.16 g)) produced regularly. The mine is also famed for its pink diamonds. In 1947, the mine's founder Dr. John Williamson presented Princess Elizabeth (later Elizabeth II) with a flawless 54-carat (10.8 g) pink diamond (the Williamson Pink Diamond) on her wedding day. The eventual 23.6-carat (4.72 g) cut diamond became the centre stone in the Williamson Diamond brooch and is supposedly the basis for the Pink Panther diamond in the film of the same name.[15]
The Williamson Mine currently has a resource of 39.6 million carats (8,000 kg) (984 million tonnes of kimberlite). It has an average mining depth of 65 metres (90m at the deepest point) and a very low stripping ratio. Energy and Minerals Minister William Ngeleja said Petra's entry is "an opportunity to breathe new life into Williamson Mine and Tanzania's diamond mining sector."[16]
See also
[edit]References
[edit]- ^ a b c "Preliminary Results Announcement for the Year ended 30 June 2023" (PDF). Petra Diamonds. Retrieved 15 February 2024.
- ^ Johan Dippenaar: Prices for both rough and polished are performing well currently and we believe that the longer-term fundamentals of the market are robust Rough & Polished, 27 June 2011
- ^ Petra Diamonds shares begin Main Market trading Mining Journal, 21 December 2011
- ^ "Where Petra Diamonds Sees Its Competitive Edge". Rapaport. 24 October 2023. Retrieved 6 February 2024.
- ^ Petra to produce 1.5m ct per year at newly-acquired Finsch Diamond mine Rough & Polished, 10 February 2011
- ^ "Petra buys De Beers' Cullinan for R1bn". Mining Weekly. 22 November 2007. Retrieved 18 October 2016.
- ^ "Tour of the Cullinan Diamond Mine (Solid)". Meet up. Retrieved 18 October 2016.
- ^ "Gemstones Diamonds Books - Farlang". Farlang. Retrieved 1 April 2015.
- ^ Exploring Africa's Gem Trail Archived 2006-09-05 at the Wayback Machine The Loupe GIA World News, Winter 2009
- ^ Dawber, Alistair (27 February 2010). "Egg-sized diamond sold to Hong Kong jeweller for a record $35m". The Independent. London. Archived from the original on 26 May 2022.
- ^ Gem's biggest diamonds The Telegraph
- ^ "Koffiefontein Diamond Mine (RSA, Petra Diamonds)". Rough & Polished. Retrieved 18 October 2016.
- ^ "Koffiefontein mine". Rough & Polished. Archived from the original on 14 March 2013. Retrieved 18 October 2016.
{{cite web}}
: CS1 maint: bot: original URL status unknown (link) - ^ Tanzania: Petra Buys De Beers 75 Percent Stake in Dar Mining Firm for $10 Million All Africa, 14 September 2008
- ^ "The Williamson Diamond Brooch: the Royal Collection". Royalcollection.org.uk.
- ^ Mixed Outlook As Diamond Giant De Beers Sells Williamson Mine to Petra All Africa, 16 September 2008