April 19, 2011

Further Encouraging Microdiamond Results from Droujba Kimberlite Pipe in Guinea

Stellar Diamonds plc, the London listed (AIM:STEL) diamond mining and exploration company focused on West Africa, reports the latest batch of microdiamond results from the Company’s 100% owned Droujba kimberlite pipe in south east Guinea.

Highlights:

  • 462 diamonds recovered from 204.15kg of kimberlite drill core sample
  • Three commercial sized diamonds recovered with the largest being 3.3mm x 2.4mm x 1.8mm
  • High percentage of diamonds described as white, colourless and transparent
  • Resource definition drill programme continuing

Karl Smithson, Chief Executive Officer, commented:

“These results provide further confirmation that the hypabyssal kimberlite of the Droujba Pipe is significantly diamondiferous. Particularly encouraging is the continued presence of commercial sized stones from what are relatively small drill core samples. In perspective 204kg would represent a cube of fresh kimberlite with approximately 420mm sides. We now intend to add these results to those previously announced in order to model the likely macrodiamond grade of the kimberlite.

“We have recently confirmed the Droujba pipe at three hectares, three times the size previously thought, and embarked on a deeper phase of drilling for resource definition purposes. We shall shortly mobilise a processing plant to Droujba for a bulk sampling programme which will further increase our confidence in the diamond grade and values.”

Microdiamond Analysis Results

Two samples of kimberlite were recently submitted to the Saskatchewan Research Council laboratory in Canada (“SRC”) for microdiamond analysis. These samples comprised 67.60kg of hypabyssal kimberlite from the main pipe and 136.55kg of hypabyssal kimberlite from the south east sub-surface intrusion which is located immediately adjacent to the main pipe.

The results from both sample batches have now been received and are considered to be consistent with previously reported microdiamond results from the hypabyssal facies of the main pipe (see news release dated 1st February 2011). A total of 462 diamonds were recovered from 204.15kg of kimberlite drill core submitted to the laboratory, with two diamonds being larger than the 0.85mm sieve and one diamond being larger than the 1.70mm sieve. The two 0.85mm sieve diamonds are classified as white, colourless and transparent, whereas the 1.70mm sieve diamond is classified as off-white and translucent and measures 3.3mm x 2.4mm x 1.8mm. All these three diamonds were recovered from the southern intrusion.

The following table summarises the caustic fusion results of these latest Droujba kimberlite samples.

Number of Diamonds According to Sieve Size Fraction (mm)

Sample

Kimberlite

Sample

+0.106

+0.106

+0.150

+0.212

+0.300

+0.425

Number

Facies

Weight (kg)

-0.075

-0.150

-0.212

-0.300

-0.425

-0.600

GN04-2011-01

Hypabyssal (Main pipe)

67.6

37

33

17

14

7

6

GN04-2011-02

Hypabyssal (South intrusion)

136.55

115

110

49

40

19

8

Total

204.15

152

143

66

54

26

14

Number of Diamonds According to Sieve Size Fraction (mm)

Sample

Kimberlite

Sample

+0.600

+0.850

+1.180

+1.700

+2.36

Total

Carats

Number

Facies

Weight (kg)

-0.850

-1.180

-1.700

-2.36

-3.350

Diamonds

+0.85mm

GN04-2011-01

Hypabyssal (Main pipe)

67.6

2

0

0

0

0

116

0

GN04-2011-02

Hypabyssal (South intrusion)

136.55

2

2

0

1

0

346

0.1401

Total

204.15

4

2

0

1

0

462

0.1401

Macrodiamond Grade Modelling

The results of these most recent analyses will be combined with those previously announced in order to forecast the macrodiamond grade of the Droujba kimberlite pipe. A total of 1,000 diamonds have now been recovered from 495.41kg of kimberlite core (approximately two diamonds per kilogramme) with eight diamonds larger than 0.85mm. This should provide sufficient material with which to undertake a first pass macrodiamond grade model.

About Stellar Diamonds plc

Stellar is a London (AIM: STEL) listed diamond mining and exploration company that has a portfolio of projects in West Africa.

Stellar owns a 100% interest in four high-grade kimberlite projects that are the focus of exploration and development. In Guinea resource definition drilling is continuing on the diamondiferous Droujba kimberlite pipe project and bulk sampling is also underway on the high grade Bouro kimberlite dyke which is adjacent to the Company’s Mandala alluvial diamond mining operation. In Sierra Leone at Tongo a bulk sampling programme is ongoing on the high grade Dyke 1 and bulk sampling is planned on the Lion 5 dyke at the Kono kimberlite project.

For further information please contact the following or visit the Company’s website at www.stellar-diamonds.com.

In accordance with the AIM Rules, the information in this announcement has been reviewed by Karl Smithson, CEO of Stellar, a qualified geologist with 22 years’ experience.

Stellar Diamonds plc

Karl Smithson,Chief ExecutiveTel: +44 (0) 20 7257 2930

Northland Capital Partners Limited

Gavin Burnell, Edward Hutton

Charles Vaughan Tel: +44 (0) 20 7492 4750

Daniel Stewart & Company plc

Martin Lampshire, Oliver Rigby Tel: +44 (0) 20 7776 6550

Pelham Bell Pottinger

Charles Vivian / James MacFarlane Tel: +44 (0) 20 7861 3232