Cesium is what happens when a “minor metal” stops behaving like a footnote and starts acting like a constraint.On InvestorNews.com, host Tracy Hughes opened her conversation with Robin Dunbar—President, CEO, and Director of Grid Metals Corp. (TSXV: GRDM | OTCQB: MSMGF)—by placing the company where it actually operates: Manitoba, with a portfolio that spans nickel-copper-PGMs at Makwa (under an option and joint venture agreement with Teck Resources Limited, which can earn up to a 70% interest by spending and paying a total of CAD$17.3 million), copper-nickel at Mayville (with an NI 43-101 open-pit resource of 32 million tonnes grading 0.61% CuEq), lithium at Donner (an NI 43-101 resource of 6.8 million tonnes grading 1.39% Li₂O, with Grid holding 75%), and the lithium–cesium story now pulling attention toward Falcon West, about 110 kilometres east of Winnipeg along the Trans-Canada Highway.Hughes didn’t waste time getting to the point. “In our InvestorTalk earlier today, you were talking about cesium,” she said, noting the “huge following” Grid has drawn on short-form video explaining why it matters. Dunbar’s answer came out with the kind of practiced urgency that suggests he has had the same conversation with end-users, financiers, and skeptics—often in the same week. “Cesium is a fascinating metal and an opportunity in the critical metal space,” he said, before narrowing the market to a startling scarcity: “There have only been three producing deposits of cesium ever globally, and there are currently only three juniors with active drill programs… globally.”The scarcity, in Dunbar’s telling, isn’t merely academic. Cesium’s best-known public-facing role is invisible: atomic clocks that underpin global positioning. But he framed it as an enabling material with both mundane and strategic pull—“high-tech and military applications,” plus drilling fluids for deep wells, and “a growing array of uses in optical and solar.” And then the line that matters most in a market built on continuity of supply: “We’re seeing interest from end users because there’s a huge shortage of cesium feedstock in the world right now.”From there, the interview snapped into geology and economics—the two languages junior miners must speak at once. Grid’s recent work at Falcon West has focused on a flat-lying pegmatite system where cesium occurs alongside lithium and rubidium. “The zone we’re drilling starts at about 20 metres down,” Dunbar explained, describing “a 1 to 3 metre zone of the mineralization we’re looking for.” The target mineral is pollucite, the principal host of high-grade cesium. “When we drill and we get pollucite, the grades we’re getting are as high as 27% over a metre,” he said, pausing just long enough for the number to register. “Globally, to find pollucite, there are just a few occurrences—it’s very hard to find.”A December 4, 2025 Grid Metals news release put those kinds of numbers into market-standard intervals, reporting high-grade intercepts including 3.45 metres grading 16.8% Cs₂O (LU25-09) and 4.0 metres grading 10.4% Cs₂O, with a 1.2-metre sub-interval at 27.1% Cs₂O (LU25-08)—results the company described as “amongst the highest Cs₂O drill intercepts reported globally, in recent years.”Hughes, speaking for an audience that lives somewhere between capital markets and chemistry, asked Dunbar to “dumb down rubidium.” He obliged by placing it in the family: rubidium is “a sister metal to cesium,” with overlapping physical properties—“very high conductivity, photovoltaic properties”—but a very different extraction reality. Cesium can occur in pollucite at extraordinary concentrations, he said, while rubidium typically sits dispersed in lepidolite and mica, “and tends to only get to a maximum of 2% to 3% in very high-grade materials.” In other words: interesting, potentially useful, but rarely the main event—unless new applications and new processing routes change the equation.