Incorporated in Guernsey. Guernsey registration Number: 47656. South African external company registration number 2009/012636/10 Share code on JSE:GML (General Segment of JSE Main Board) / AIM:GEM ISIN: GG00BG0KTL52 | LEI: 21380017GAVXTCYS5R31 ("Gemfields" or the "Company") Auction Results – Higher-quality emeralds LONDON, 12 SEPTEMBER 2025 Gemfields announces the results of an auction comprised of higher-quality rough emeralds held during the period 25 August – 11 September 2025. Highlights: August-September 2025 Higher-Quality Emerald Auction • Total auction revenues of USD 32.0 million • 38 lots were offered for sale, of which all were sold (100%) • Average realised price of USD 160.78 per carat • The 52 auctions of Kagem gemstones held since July 2009 have generated USD 1,122 million in total revenues • The auction included an exceptional gemstone named Imboo (‘buffalo’), weighing 11,685 carats. Imboo is the latest, and largest, remarkable gemstone discovered at the Kagem mine. Gemfields Group Limited, Royal Chambers, St Julian’s Avenue, St Peter Port, GY1 4HP, Guernsey T +44 (0)1481 731 554 gemfieldsgroup.com Adrian Banks, Gemfields’ Managing Director of Product & Sales, commented: “This September auction marks Kagem’s first high-quality emerald sale since the disappointing result in November 2024. Mining operations at Kagem were suspended in January 2025 in response to market uncertainty and challenges relating to the oversupply of Zambian emeralds. Following signs of recovery at the April commercial-quality auction, two mining points were reopened in May. While the wider market continues to navigate mixed sentiment and tariff uncertainty, today’s auction result has validated these decisions and delivered a highly positive outcome. Strong demand was evident across the grades, with robust prices achieved. We are grateful to our customers for their continued support and recognition of the quality of Kagem’s emeralds, as reflected in the prices realised. As market leaders, we remain committed to managing supply responsibly and in the best interests of our customers and downstream partners. A huge thanks goes out to the Kagem team for their hard work and dedication in achieving this result.” The auction lots were made available for private, in-person viewings by customers in Bangkok. Following the viewings, the auctions took place via an online auction platform specifically adapted for Gemfields and which permitted customers from multiple jurisdictions to participate in a sealed-bid process. The rough emeralds sold were extracted by Kagem (which is 75% owned by Gemfields and 25% by the Industrial Development Corporation of Zambia). The proceeds of this auction will be fully repatriated to Kagem in Zambia with all royalties due to the Government of the Republic of Zambia being paid on the full sales prices achieved at the auction. The results of the five most recent Higher-Quality Kagem auctions are summarised in the table below (and earlier results are available at www.gemfieldsgroup.com): AUCTION Nov ’22 May-Jun ’23 May ’24 Nov ’24 Sep ’25 RESULTS AUCTION AUCTION AUCTION AUCTION ** AUCTION (HIGHER (5 sequential (5 sequential (5 sequential (5 sequential (5 sequential QUALITY) mini-auctions) mini-auctions) mini-auctions) mini-auctions) mini-auctions) 30 Oct – 17 15 May – 1 Jun 13 – 30 May 4 – 21 Nov 25 Aug – 11 Dates Nov 2022 2023 2024 2024 Sep 2025 Bangkok / Bangkok / Bangkok / Bangkok / Bangkok / Location Online Online Online Online Online Higher Higher Higher Higher Higher Type Quality Quality Quality Quality Quality Carats offered 426,180 264,132 240,000 200,460 199,103 Carats sold 401,180 264,132 208,990 141,084 199,103 No. of companies 50 69 60 56 65 placing bids No. of lots 37 35 46 43 38 offered No. of lots sold 34 35 43 30 38 Gemfields Group Limited Page 2 of 5 Percentage of 92% 100% 93% 70% 100% lots sold Percentage of lots sold by 94% 100% 87% 70% 100% weight Total sales USD 30.8 USD 43.7 USD 35.0 USD 16.1 USD 32.0 realised at million million million million million auction Average per USD USD USD USD USD carat sales 160.78/carat * 76.78/carat 165.55/carat 167.51/carat 113.96/carat value * Includes the 37kg ‘Kafubu Cluster’, which comprised 44% of the weight offered at the auction. ** The table above excludes the special ‘second-round’ auction of unsold lots from the November 2024 high-quality auction, which were re-offered for sale in February 2025. This special auction achieved revenues of USD 4.8 million with 10 of the 13 lots sold (77%), representing 45,864 carats sold out of 59,192 carats on offer (77%) at an average sales price of USD 105.49 per carat. The specific auction mix and the quality of the lots offered at each auction vary in characteristics such as size, colour and clarity on account of variations in mined production and market demand. Therefore the results of each auction are not always directly comparable. -ENDS- Further information on Gemfields Group Limited can be found at: GEMFIELDSGROUP.COM To join our investor mailing list, please contact us on: ir@gemfields.com For any press enquiries, please contact Helena and Albertina: helena.choudhury@gemfields.com / albertina.namburete@gemfields.com This announcement contains inside information for the purposes of Article 7 of the Market Abuse Regulation (EU) no. 596/2014 which forms part of domestic UK law pursuant to the European Union (withdrawal) act 2018 ("MAR"). Gemfields Group Limited Page 3 of 5 ENQUIRIES GEMFIELDS Sean Gilbertson / David Lovett / Heinrich Richter ir@gemfields.com T: +44(0) 20 7518 3400 SPONSOR (JSE) Investec Bank Limited NOMINATED ADVISER Panmure Liberum (AIM) & BROKER Scott Mathieson / Amrit Mahbubani / John More T: +44(0) 20 3100 2222 GEMFIELDS HEAD OFFICE Helena Choudhury / Albertina Namburete PR, LONDON helena.choudhury@gemfields.com / albertina.namburete@gemfields.com Gemfields Group Limited Page 4 of 5 ADDITIONAL INFORMATION ON GEMFIELDS Gemfields is a world-leading responsible miner and marketer of coloured gemstones. Gemfields is the operator and 75% owner of both the Kagem emerald mine in Zambia (believed to be the world’s single largest producing emerald mine) and the Montepuez ruby mine in Mozambique (one of the most significant recently discovered ruby deposits in the world). In addition, Gemfields also holds controlling interests in various other gemstone mining and prospecting licences in Zambia, Mozambique, Ethiopia and Madagascar. Gemfields has developed a proprietary grading system and a pioneering auction platform to provide a consistent supply of coloured gemstones to downstream markets, a key component of Gemfields’ business model that has played an important role in the growth of the global coloured gemstone sector. GEMFIELDS GEMFIELDS.COM | INVESTORS |FOUNDATION INSTAGRAM | FACEBOOK | X | YOUTUBE KAGEM MINING LINKEDIN MONTEPUEZ RUBY MINING LINKEDIN Gemfields Group Limited Page 5 of 5