Our Diamonds

The Letšeng mine in Lesotho produces the highest quality gem diamonds, consistently achieving the highest price per carat of any kimberlite mine in the world. It is also famous for its large top colour white diamonds, and has produced four of the 20 largest white diamonds ever recorded since Gem Diamonds took the mine over in 2006.

Letseng Star

The ultimate gem

Diamond types are classified by nitrogen content, namely Type I and Type II. Type I diamonds contain nitrogen while Type II diamonds are nitrogen free and are usually white or blue. Type IIa and Type IIb (blue colour) are very rare and generally thought to comprise less than 1% of all diamonds. While it is possible to obtain D Flawless diamonds from Type I diamonds, the most sought after diamonds are Type IIa Flawless diamonds. Type II diamonds have superior optical properties and have a superior overall polish to Type I diamonds.

In ancient times, incredible white diamonds were recovered in Golconda in India, and to this day Golconda diamonds have held a superior position to white diamonds produced anywhere else in the world. However, notwithstanding these Golconda gems, the Gem Diamonds Marketing Consultants and some of the world's leading Diamantaires believe that the D Flawless diamonds from Letšeng are the prize gems of them all.

Rough gem quality diamonds

These diamonds are attractive when viewed and are the easiest diamonds to manufacture and polish for jewellery.

The value of a diamond is based on rarity.

Gem quality diamonds are based on the combination of the following characteristics:


To a large degree size does matter, especially with large white D, E F & G colours. However, when dealing with rare fancy colours such as reds, blues, oranges and greens, even small stones are highly prized gems.


A range of colourless, moving to lighter yellows and browns are regarded as gem colours. The closer a diamond is to colourless, the more valuable it becomes. Deeper colours of yellow and brown, as well as rare colours such as orange, violet, purple, green, pink, blue and red are referred to as fancy colours.


Originally gem quality rough diamonds were those diamonds without cracks, twins or large inclusions, the equivalent of the polished grade SI3 or better. Lesser qualities were referred to as near-gem and included low clivage and semi-opaque rejection material.

In today's terminology, the better near-gem qualities are included as gem quality, as it is now viewed that any diamond which can provide a polishable gem be included, regardless of the fact that more splits (sawing, cleaving or lasering) are required to achieve polishable pieces.


The most desired rough gem shapes are the following:

  • crystals (Sharp edged octahedrons),
  • octahedrons with some rounding to the edges and points
  • dodecahedrons
  • triangular maccles
  • rounded dodecahedral maccles
  • shapes that have high yielding forms either for rounds or fancy cuts

Less desirable gem shapes are cubes, irregular low yielding shapes and twinned or aggregated forms.

Other factors which influence the overall gem description would include stones with unattractive clouds, milkiness or colour banding/zoning.

Therefore, the most desired rough gem diamonds would be those having good colour, shape and internal clarity, without ignoring the size factor.

Polished gem diamonds

Based on the descriptions, a polished gem diamond requires the basic 4 C's:

Carat weight

Larger diamonds are rare. The size of the polished gem does matter and is further complicated by reaching stipulated price bands, such as 0.25ct, 0.50ct, 1.00ct, 3.00ct, 5.00ct, and 10.00ct and so on. The price difference between a 0.99 carat and a 1.00 carat is very high and this continues throughout all the size bands.


Diamonds come in many different colours. The colour of most diamonds range from colourless to light yellow or brown. Normal diamonds are graded on a colour scale which ranges from D (colourless) to Z (light yellow). Within this range colourless diamonds are the most rare, and the most valuable. Diamonds that are blue, pink, purple, orange, red, green or canary yellow are called "fancy colours", and are very rare.


The clarity of a polished diamond is the relative absence of inclusions or blemishes. The top clarity grade is "Flawless" and diamonds graded as such are rare. The clarity of a diamond has a direct influence on the value of a polished diamond. Therefore, the higher the clarity, the more prized and expensive the polished gem becomes.


Round Brilliant cut diamonds are more expensive than fancy shaped diamonds. This is because in the polishing process more weight is lost when polishing a Round Brilliant than when polishing a fancy shape as the latter is polished to maximise the polished weight recovered from the rough diamond.

Other important factors for polished gem diamonds

Quality of polish

It is estimated that of all the diamonds mined only 0.001% will produce D Flawless finished stones. [Bryan Boyne, G.G. (GIA)].

The quality of polish and symmetry is vital to achieve maximum brilliance, scintillation ('sparkle') and dispersion ('fire').

Famous Letšeng Diamonds

The Lesotho Brown (601ct)

The Lesotho Brown

The Blue diamond (12ct)

The Blue Diamond

The Lesotho Promise (603ct)

The Lesotho Promise

The LETŠENG Legacy (493ct)

The Letseng Legacy

The Light of LETŠENG (478ct)

The Light of Letseng

The LETŠENG Star (550ct)

The Letseng Star

The Yellow Diamond (299ct)

The yellow diamond

The LETŠENG Destiny (314ct)

The Letseng Destiny

The LETŠENG Dynasty (357ct)

The Letseng Dynasty

The Lesotho Brown

The Lesotho Brown

The 601ct Lesotho Brown

Discovered in 1967, the 601 carat Lesotho Brown diamond was the first significant diamond to be recovered at Letšeng and led to the formal development of the Letšeng mine. The Lesotho Brown was discovered by Ernestine Ramaboa who is reputed to have walked for four days and four nights to deliver it into the safekeeping of a reputable diamond buyer. Harry Winston acquired the diamond, and the cleaving of the Lesotho Brown Diamond into two pieces was broadcast live on American television in 1968. The polishing was completed in a year and resulted in eighteen gemstones, the largest of which was the Lesotho I, a 71.73 carat flawless emerald cut diamond with a pale pink hue.

The Blue Diamond

The Blue Diamond

12 carat Blue diamond

This rare 12.47 carat blue diamond was recovered at Letšeng in September 2013. It was sold a month later on tender in Antwerp for a record price of US$603 047 per carat (US$7.5 million), the highest US$ per carat for any Letšeng rough diamond sold to date.

The Lesotho Promise

The Lesotho Promise

The 603ct Lesotho Promise

Gem Diamonds recovered the 603 carat Lesotho Promise at its Letšeng mine in August 2006. The Lesotho Promise is currently ranked as one of the world's largest white diamond on record and the largest diamond to emerge from the Letšeng mine to date. The Lesotho Promise was sold for US$12.4 million to SAFDICO, the manufacturing arm of Graff Jewellers, at an auction in Antwerp in October 2006.

The Lesotho Promise was subsequently polished into 26 D flawless and internally flawless diamonds, the largest of which was a 76.4 carat pear-shaped diamond. The diamonds were fashioned into a single necklace by Graff.

The Letšeng Legacy

The Letseng Legacy

The 493ct Letšeng Legacy

The Letšeng Legacy is currently ranked as one of the largest rough white diamonds ever recovered and was named to reflect the growing legacy that the Letšeng mine in Lesotho is creating as a producer of significant large white diamonds.

This remarkable 493 carat diamond, discovered in September 2007, was sold at an auction in Antwerp to SAFDICO, the manufacturing arm of Graff Jewellers, for US$10.4 million in November 2007.

The Light of Letšeng

The Light of Letseng

The 478ct Leseli La Letšeng (Light of Letšeng)

The Leseli La Letšeng, which means Light of Letšeng, is a 478 carat D colour white diamond that was recovered from the Letšeng mine in Lesotho in September 2008. The name reflects the diamond's remarkable colour and clarity, the highest possible quality for a white diamond. The diamond is currently ranked in the top twenty largest rough white diamonds ever to be recovered and was the third significant recovery from Letšeng in as many years. The fame of this diamond extends further in that it revealed a 102.79 carat round shaped, D colour internally flawless diamond, making it the largest round shaped polished diamond ever to be graded. A further 10 exquisite polished diamonds were also revealed.

Light of Letšeng was sold on tender in Antwerp in November 2008 for US$18.4 million, to SAFDICO, the manufacturing arm of Graff Diamonds. The price represented an extraordinary price per carat of US$38 400, against a global average diamond price of US$90 per carat.

The Letšeng Star

The Letseng Star The Letseng Star The Letseng Star

The 550ct Letšeng Star

The 550ct Letšeng Star was recovered from the Letšeng mine on 19 August 2011 and named in a gala evening held in Maseru, the capital of the Kingdom of Lesotho on Monday 19 September. The name was given to signify the growing number of "stars" in Letšeng's growing constellation of large diamonds recovered. The Letšeng Star is also ranked as one on the the largest white rough diamonds on record and the second largest white diamond to be recovered at Letšeng. This diamond yielded 12 pairs of pear shaped diamonds, as well as a main polished stone of 33.11 carats, also a pear shape, to form a unique collection of over 165 carats of D flawless and internally flawless polished gems stemming from this single rough diamond.

The Yellow Diamond

The Yellow Diamond

The 299 carat Yellow Diamond

This diamond was recovered in December 2014. In line with the group’s strategic goal to maximise the revenue achieved from remarkable diamonds, a partnership arrangement was undertaken with Safdico, a subsidiary of Graff Diamonds in January 2015. Unmasking its true radiance, the gem was cut and polished by expert artisans with coloured diamond expertise, which resulted in a magnificant 132.55 carat fancy intense yellow cushion shaped polished diamond, along with eight other yellow diamonds, the largest being a 21.34 carat fancy yellow pear shape. The 132.55 carat gem, aptly named The Golden Empress, was set into a breathtaking Graff signature necklace, adorned with 30 other cushion cut yellow diamonds.

The Letšeng Destiny

The Letseng Destiny

The 314 carat Letšeng Destiny

The Letšeng Destiny was recovered in May 2015 and sold into a partnership arrangement in June 2015. The name was given to signify a hidden power believed to control future events. The Letšeng Destiny has yielded a main polished fancy shape diamond of over 100 carats D colour flawless and 12 smaller diamonds of D colour, totalling a polished weight of 164 carats.

The Letšeng Dynasty

The Letseng Dynasty

The 357 carat Letšeng Dynasty

The Letšeng Dynasty was recovered in July 2015 and sold for US$19.3 million in September 2015, achieving the highest value ever to be achieved for a single Letšeng diamond. The name given was to symbolise the succession of diamonds from the same family.