More evidence of softening lithium prices has emerged, with the operators of Western Australia's Mount Marion mine revealing they will be paid 13 per cent less for their product in the final three months of 2018 than in the previous quarter.

While prices remain strong by historical standards, the $US930 per tonne price agreed for Mt Marion's spodumene concentrate in the final three months of 2018 was well below the $US1070 per tonne price achieved in the three months to September 30.