Viridis Mining and Minerals (ASX:VMM) manufactured the first batch of high-grade mixed rare earth carbonate at its demonstration plant in Poços de Caldas, Brazil, according to a Tuesday filing with the Australian bourse.

The plant is currently processing ionic clay feed sourced from the Colossus Project Northern Concessions, with the ore feed expected to support the proposed mine plan's early years.

As the demonstration plant is now operational, Viridis plans to advance key initiatives, including producing mixed rare earth carbonate samples "for potential offtake partners currently in advanced discussions," the company said.

"Very few Western rare earth companies possess the in-house capability to continuously process ionic clay material at scale, into a saleable [mixed rare earth carbonate] product," said Viridis Managing Director Rafael Moreno.