Comet Lithium Expands Discovery Work at Elmer East, Confirming a Continuous Caesium Pegmatite Over More Than 200 Metres

A well-developed caesium-rich LCT-type pegmatite system, with all five channels returning elevated to high concentrations of caesium, tantalum, and lithium.

Comet Lithium Corp. (TSXV: CLIC) (FSE: 8QY) ("Comet Lithium" or the "Corporation") is pleased to announce results from its October 2025 channel sampling program at the Elmer East Project in the Eeyou Istchee James Bay region of Québec. The program identified several out crops of high-grade caesium-dominant LCT pegmatites extending over more than 200 metres of projected strike. The five sawn channel samples collected along the trend returned strong caesium grades along with significant tantalum, and lithium values. Importantly, the 200 metre corridor represents only the currently exposed portion of the system. Geological and structural mapping indicate the mineralized trend may extend beyond current exposures, and additional parallel dykes have already been identified.

These results elevate Elmer East into a rare class of global discoveries. High-grade primary caesium systems are uncommon, with only a handful of notable examples worldwide (Tanco, Sinclair, Bikita). The continuity, grade, and multi-element enrichment now documented at Elmer East position Comet Lithium at the forefront of a rapidly emerging critical-mineral opportunity.

Global Significance of the Discovery

High-grade primary cesium pegmatites are among the rarest critical-mineral systems on Earth. Only three deposits globally: Tanco (Canada), Sinclair (Australia) and Bikita (Zimbabwe) have ever been commercially mined for caesium¹. The multi-percent Cs₂O grades, accompanying Ta₂O₅ and Rb enrichment, and structural continuity observed at Elmer East are all characteristic of this very small class of deposits.

These results suggest Comet Lithium may be delineating the first significant caesium-rich LCT system ever identified in the James Bay region, underscoring the strategic importance of this discovery. Given the growing demand for caesium in advanced electronics, perovskite solar, aerospace alloys, quantum technologies, and specialized chemical applications, Elmer East represents a potential cornerstone discovery within Canada's critical mineral landscape.

The exploration results disclosed herein are early-stage in nature, and additional work is required to fully understand the extent, continuity, and significance of the mineralized system.

Program Highlights:

• All five channels cut across the mineralized corridor returned high-grade caesium, with robust Li₂O, Ta₂O₅ and Rb support.
• Mineralized trend now confirmed over 200 metres, remaining open in all directions.
• Multiple intervals returned > 4% Cs₂O, characteristic of pollucite-bearing or pollucite-proximal LCT systems (Figure 1).
• The strength and consistency of results indicate potential for a significant caesium asset, a category with only a handful of global peers.
• Preparations advancing for a 2026 drilling program.

Detailed Channel Results

CH-1 (EE25-CH1)

• 2.45 m @ 1.11% Li₂O, 469 ppm Ta₂O₅, and 3.39% Cs₂O
  • Including 1.0 m @ 0.49% Li₂O, 375 ppm Ta₂O₅, and 4.91% Cs₂O

CH-2 (EE25-CH2) (open to the north and south)

• 3.0 m @ 1.97% Li₂O, 866 ppm Ta₂O₅, and 2.27% Cs₂O
  • Including 0.5 m @ 1.15% Li2O, 495 ppm Ta₂O₅, and 3.75% Cs2O and,
  • Including 2.0 m @ 2.35% Li₂O, 1,045 ppm Ta₂O₅, and 2.06% Cs₂O

CH-3 (EE25-CH3) (open to the south)

• 3.2 m @ 1.20% Li₂O, 520 ppm Ta₂O₅, and 2.45% Cs₂O
  • Including 0.5 m @ 1.02% Li₂O, 477 ppm Ta₂O₅, and 4.66% Cs₂O

CH-4 (EE25-CH4) (open to the north and south)

• 2.2 m @ 1.22% Li₂O, 1160 ppm Ta₂O₅, and 2.18% Cs₂O
  • Including 0.5 m @ 1.04% Li₂O, 694 ppm Ta₂O₅, and 4.19% Cs₂O

CH-5 (EE25-CH5) (open to the north and south)

• 3.0 m @ 1.13% Li₂O, 929 ppm Ta₂O₅, and 1.35% Cs₂O
  • Including 1.5 m @ 1.26% Li₂O, 1,315 ppm Ta₂O₅, and 2.09% Cs₂O

Geological Observations

The October program was the second phase following the Company's August grassroots discovery and we have now defined:

• A wide, mineralized LCT pegmatite corridor
• Strong enrichment in Cs₂O, Ta₂O₅, Rb and Li₂O
• Multiple internal zones with > 4% Cs₂O, comparable to grades historically mined at caesium operations
• Structural continuity suggesting a large, evolving pegmatite system, open along strike and at depth

These grades and zonation patterns are hallmarks of pollucite-rich caesium systems, known for their rarity, strategic value, and high commodity pricing.

Comparable Global Systems

The grades reported at Elmer East, including multiple > 4% Cs₂O intervals, are consistent with the high-grade zones historically mined at the Tanco mine in Manitoba, the Sinclair mine in Australia, and the Bikita mine in Zimbabwe. These deposits supplied the global caesium market for decades. Comparisons at this early stage provide valuable context to the emerging potential of Elmer East, particularly as caesium-rich pegmatites remain extremely rare in modern exploration.

References to deposit analogues are for geological context only and there is no certainty that the Elmer East Project will exhibit similar grades, tonnages, mineralogy, or economic potential.

Next Steps

• Final structural mapping and drillhole planning over the 3D modelled mineralized corridor
• Potential additional mechanical stripping to extend exposures
• Drill permit amendments and pad planning
• 2026 drill program to test depth, thickness, and potential additional parallel pegmatites

"In management's view, Elmer East is now clearly emerging as a leading caesium discovery, these type of deposits are rare. The continuity we are seeing over 200 metres, combined with consistently high grades across the channel samples, is great. Caesium-dominant LCT pegmatites are rare, and to find one of this scale, grade and multi-element enrichment in James Bay is remarkable. Elmer East is quickly becoming one of Comet's most strategic assets, and we are accelerating work to get drills turning in 2026." commented Vincent Metcalfe, Chair and CEO of Comet Lithium.

Cautionary statements

Channel sample intervals represent sample lengths and may not represent true widths. Grab samples are selective by nature and may not be representative of mineralized zones.

QAQC

A Quality Assurance / Quality Control 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, Québec.

All assays reported were analyzed at AGAT Laboratories in Mississauga, Ontario for multi-element using sodium peroxide fusion and ICP-OES/ICP-MS finishes under AGAT Laboratories code 210378. In the case of overlimit for Caesium (>10,000 ppm), assays were analyzed under package 201-179 using sodium peroxide fusion and ICP-OES finish.

Qualified Person

Vincent Cardin-Tremblay, P. Geo (ogq #1386, PGO #3347), registered in the Provinces of Québec, and Ontario is Vice President 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 Consulting Ltd. 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, AB, CAN, Montreal, QC, CAN, and Denver, CO, USA, 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 Corporation

Comet Lithium is a dynamic exploration company with a growing portfolio of highly prospective assets located in Québec, 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. Comet Lithium has 29,710,953 common shares outstanding.

Forward-Looking Statements

This news release contains statements that may constitute "forward-looking information" within the meaning of applicable Canadian securities legislation. Forward-looking information may include, among others, statements regarding the future plans, costs, objectives or performance of Comet Lithium, or the assumptions underlying any of the foregoing. In this news release, words such as "may", "would", "could", "will", "likely", "believe", "expect", "anticipate", "intend", "plan", "estimate" and similar words and the negative form thereof are used to identify forward-looking statements. Forward-looking statements should not be read as guarantees of future performance or results, and will not necessarily be accurate indications of whether, or the times at or by which, such future performance will be achieved. No assurance can be given that any events anticipated by the forward-looking information will transpire or occur, including if any planned exploration programs on the Elmer East Property, including the planning of potential drilling in 2026 described in this press release, will occur, the timing to conduct such exploration program and the results of such exploration programs, and if it does so, what benefits Comet Lithium will derive from any such exploration programs. Forward-looking information is based on information available at the time and/or management's good-faith belief with respect to future events and are subject to known or unknown risks, uncertainties, assumptions and other unpredictable factors, many of which are beyond Comet Lithium's control. These risks, uncertainties and assumptions include, but are not limited to the risks, uncertainties and assumptions described under "Financial Instruments" and "Risk and Uncertainties" in Comet Lithium's Annual Report for the fiscal year ended December 31, 2024, a copy of which is available on SEDAR+ at www.sedarplus.ca, and could cause actual events or results to differ materially from those projected in any forward-looking statements. Comet Lithium does not intend, nor does it undertake any obligation, to update or revise any forward-looking information contained in this news release to reflect subsequent information, events or circumstances or otherwise, except if required by applicable laws.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of the release.

Website: CometLithium.com

SOURCE Comet Lithium Corporation