Comet Lithium samples 1.85% Li, 23,100 ppm Cs at Elmer

Mr. Vincent Metcalfe reports COMET LITHIUM REPORTS HIGH-GRADE CAESIUM AND LITHIUM ASSAY RESULTS FROM GRASSROOTS PEGMATITE DISCOVERY AT ELMER EAST PROJECT, JAMES BAY, QUEBEC Comet Lithium Corp. has released the assay results from the recently completed exploration program at its 100-per-cent-owned Elmer East project, located in the Eastmain greenstone belt, James Bay region, Quebec. The program, conducted from June 25, 2025, to June 30, 2025, has returned high cesium and lithium assay values ) from a newly discovered spodumene-bearing pegmatite dike. Additionally, a trend to the east of the dike discovery spanning over six kilometres has returned very good potassium-to-rubidium ratios, confirming the fertile nature of the system and high prospectivity of the property. All 252 assay samples from the initial program have been received. Follow-up to spodumene-bearing pegmatite dike discovery As previously disclosed on July 9, 2025, Comet Lithium's field team, led by Dahrouge Geological Consulting Ltd., identified a grassroots LCT-type (lithium-caesium-tantalum) pegmatite dike in the southwestern portion of the southern claim block. This discovery represents a great outcome given the program's short duration. Pegmatite dike characteristics: Measures between one and two metres in width, and has been traced for approximately 80 metres in outcrop; Remains open to the east, with its western extent pinching out; Hosts spodumene, along with muscovite and tourmaline, mineralogy consistent with highly evolved LCT pegmatite systems; To date, only two grab samples have been collected from the dike (see the attached table), both returning high assay results. Assay highlights Two grab samples from the dike, located approximately 65 metres apart, have returned outstanding grades, as detailed in the attached table. Flagship sample E6481203: Lithium (Li): 8,640 parts per million (ppm) Li -- 1.86 per cent Li2O; Cesium (Cs): 23,100 ppm Cs -- 2.46 per cent Cs2O; Tantalum (Ta): 610 ppm Ta -- 745 ppm Ta2O5; Rubidium (Rb): 3,810 ppm Rb -- 0.42 per cent Rb2O; Also notable: gallium (Ga) (75 ppm). In addition to high-grade cesium and lithium grades, the dike also returned highly elevated tantalum, rubidium and gallium values. Across the property, seven samples returned rubidium (Rb) values over 1,000 ppm (1,094 ppm Rb2O), with three exceeding 2,000 ppm (2,188 ppm Rb2O). Seven samples returned gallium values over 50 ppm, with three exceeding 75 ppm. These geochemical signatures are consistent with highly evolved LCT-type pegmatites and reinforce the fertile nature of the Elmer East system. "Discovering such extraordinary cesium and lithium grades at surface, during our first exploration program at Elmer East, marks a transformational milestone for Comet Lithium," stated Vincent Metcalfe, chair and chief executive officer of Comet Lithium. "Cesium grades of this magnitude are exceptionally rare and represent a strategically important critical mineral, particularly when combined with significant lithium values. The geochemical signature, with high fractionation indicators and favourable K/Rb ratios, confirms the fertile nature of the system and underscores the highly prospective potential of the property, especially around the newly identified dike. Given that this discovery was made on the second-to-last day of the program, we are confident that we have only begun to uncover Elmer East's full potential," added Mr. Metcalfe. Geological context The newly discovered dike lies along a prominent north-northeast-south-southwest regional structure, interpreted from magnetic survey data, within amphibolite crosscut by tonalitic and pegmatitic intrusions. Outcrop exposure is excellent (approximately 75 per cent) and the dike remains open along strike, providing strong potential for additional discoveries. Geochemically, the pegmatite demonstrates advanced fractionation, as reflected in elevated Cs, Rb and Ta contents. Potassium-to-rubidium (K/Rb) ratios remain within a favourable range, consistent with highly evolved LCT systems capable of hosting both lithium and cesium mineralization of potential economic significance. Cesium market context Cesium is one of the rarest critical minerals, with a highly specialized and niche market. To date, only three deposits globally have ever been commercially mined for caesium: the Tanco mine in Manitoba, Canada; the Bikita mine in Zimbabwe; and the Sinclair mine in Western Australia, which has since been depleted. Supply today is extremely limited, with Tanco historically being the world's primary source. Cesium is listed as a critical mineral by the United States, Canada and the European Union due to its scarcity and strategic applications in areas such as advanced electronics, defence and aerospace, specialty glass, oil and gas drilling fluids, and atomic clocks. Next steps With all assay results now in hand, Comet Lithium will: Conduct and undertake detailed geological mapping and structural analysis to identify additional pegmatite dikes; Plan a targeted follow-up program, including trenching and channel sampling; Prioritize evaluation of strike length, depth continuity and mineral zonation of the caesium- and spodumene-bearing dike. Cautionary statements Grab samples are selective by nature and may not be representative of mineralized zones. QA/QC (quality assurance/quality control) A QA/QC protocol following industry best practices was incorporated into the sampling program. All rock samples were collected under the supervision of Comet Lithium and Dahrouge Geological Consulting employees. All samples were logged and photographed on site while being collected. Samples were then bagged, and blanks and certified reference materials were inserted at regular intervals. Groups of samples were placed in large bags, sealed with numbered tags in order to maintain a chain of custody and shipped to AGAT Laboratories in Val d'Or, Que. All assays reported were analyzed at AGAT Laboratories in Mississauga, Ont., for multielement using sodium peroxide fusion and ICP-OES/ICP-MS (inductively coupled plasma optical emission spectroscopy/inductively coupled plasma mass spectrometry) finishes under AGAT Laboratories code 210378. In the case of overlimit for cesium (more than 10,000 ppm), assays were analyzed under package 201-179 using sodium peroxide fusion and ICP-OES finish. Qualified person Vincent Cardin-Tremblay, PGeo (ogq No. 1386, PGO No. 3347), registered in the provinces of Quebec and Ontario, vice-president of exploration to Comet Lithium, is a qualified person under National Instrument 43-101, Standards of Disclosure for Mineral Projects. He has reviewed the technical contents of this news release and has approved the disclosure of the technical information contained herein. About Dahrouge Geological Consulting Ltd. Dahrouge Geological is a global mining and mineral exploration consulting group providing expertise in professional geological, logistical and project management services through all stages of the mining value chain. Based in Edmonton, Alta., Montreal, Que., and Denver, Colo., Dahrouge and its predecessor, Halferdahl and Associates, have advised and assisted clients in identifying, exploring, developing and optimizing mineral projects and resources since 1971. About Comet Lithium Corp. Comet Lithium is a dynamic exploration company with a growing portfolio of highly prospective assets located in Quebec, including several properties in the prolific James Bay district. The company's land package includes the Liberty property, located adjacent to Winsome Resources' Adina lithium discovery, and the Troilus East property, positioned next to Troilus Gold's gold-copper project. Comet's strategy is focused on systematic exploration and unlocking the value of its diverse property portfolio through targeted fieldwork and strategic partnerships. We seek Safe Harbor.