The discovery of a rare 12.47 carat blue diamond (pictured above) and an 83.8 carat 'exceptional quality' white diamond by Gem Diamonds (GEMD) at its Letseng deposit in Lesotho sends the miner up 6.3% to 152p. Gem remains one of our top picks in the diamond sector. Investec notes that mining at Letseng is moving into higher grade areas of the deposit so there is an 'increased likelihood of high value stones being recovered'.

Pawnbroker Albemarle & Bond (ABM:AIM) falls 43.5% to 70.6p on news that a deterioration in trading, as predicted by Shares, means it is now at risk of breaching its banking covenants. It has also announced plans for an emergency rights issue. We look at the situation in more detail here.

South East Asian oil explorer Salamander Energy (SMDR) falls 12.7% to 113.5p after it reports a well on its Ayutthaya prospect in Block G4/50 in the Gulf of Thailand will be plugged and abandoned as a dry hole. This overshadows news of a positive results from development drilling on its Sinphuhorm field onshore Thailand.

Mobile marketing and content supplier InternetQ (INTQ:AIM) turns in strong half-year growth across both the core areas, plus near 100% cash conversion. The market has warmed to this story thanks to excellent organic growth with bolt-on acquisitions adding extra value, and investors bid the shares 3p higher to 325p.

Car dealer enterprise software supplier Incadea (INCA:AIM) gets a hammering, the shares slumping 11% to 109p on slow interim revenue growth and cash generation. Licences are moving in the right direction, up 13%, but a key move into Russia is taking longer to pay off. Management remain upbeat that the tide will turn in the second half, and a ?1.3 million contract win offers encouragement for one of our running Plays of the Week.

February's Aim-IPO seems to have taken its toll on security and tracking kit supply microcap Starcom (STAR:AIM) with the hoped-for ramp-up of Helios and Watchlock lines suffering. That'll mean a sales and profits miss this year for one of our running Plays of the Week, sending the shares spinning over 15% lower to 21.5p, although the company reckons it will all work out in 2014.

Kurdistan oil explorer Gulf Keystone Petroleum (GKP:AIM) slips 3.1% to 188.8p after Sunday's suicide bombing in Erbil, the capital of the semi-autonomous region of Iraq. The company describes itself as 'saddened' by the attack which killed six and left more than 40 people injured. Genel Energy (GENL), which also has significant interests in the area, is down 3.1% to 943.5p.

Housebuilder MJ Gleeson (GLE) sheds 2.1% to 332.8p as investors take profit after the £178.3 million cap posts a 91% rise in full-year profit before tax to £5.8 million. The group sees its forward order book increase by 141% to £25.9 million.

Heavy construction specialist Keller (KLR) adds 1.9% to 1,021p after the group annouces a major contract win in Singapore. Keller's contract to construct foundations and related works for the new Sengkang hospital project in Singapore is worth approximately £33 million.

Drug developer Xenetic BioSciences (XEN: AIM) slips 5.6% to 6.1p on plans for a fundraising to finance its activities next year. This is the result of a £200,000 increase in cash-burn to £450,000 during the first half of the year, where pre-tax losses narrowed to £1.3 from £1.8 million a year ago.

Transplant technology specialist Lifeline Scientific (LSI: AIM) falls 4.2% to 177.5p on weak interims. Its pre-tax losses widened to £1.4 million from £275,101 a year ago. Its cash also fell after burning £1.8 million during the period, up from £200,000 at the half way stage of 2012.

Respiratory drug specialist Verona Pharma (VRP: AIM) slips 2.1% to 2.2p as its pre-tax losses remain flat at around £1 million, while management do not expect any significant achievements in the remainder of the year.

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Issue Date: 30 Sep 2013