Glossary · Geology
Grade
The concentration of the target commodity in the rock — units depend on the commodity.
Grade expresses how much of the target commodity is in the rock. Units are commodity-specific: gold and silver typically in grams per tonne (g/t), copper and other base metals in percent (%), uranium in parts per million (ppm) or pounds per tonne (lb/t), lithium in percent Li₂O. Headline grade in a drill result refers to the grade of the best intercept; the deposit's average grade across the resource is the figure investors use to compare projects.