Leonardite was named after A. G. Leonard, first director of the North Dakota Geological Survey, in recognition of his valuable work on these deposits. Leonardite is a soft, dark colored, vitreous mineraloid that contains high concentrations of the active humic acid (>65%) and fulvic acid (≈4%). Leonardite is an oxidation product of lignite coal and mined from near surface pits.
The commercial applications of leonardite are driven by the utilization of the humic acid and fulvic acid constituents. Significant market applications of leonardite are in the oil well drilling industry, agricultural applications as plant growth aid and soil conditioner, and clay dispersant in the metalcasting industry. Additional specialty applications include remediation of soil contamination and water treatment.