A water-based, non-toxic, acrylic wash manufactured by Games Workshop. 
It is a multi-purpose brown wash designed to flow into the recesses of plastic, metal, and resin miniatures to create natural-looking shadows and depth with minimal effort.
The low surface tension formula ensures the paint naturally runs off flat areas and pool inside crevices, instantly creating shadows that accentuate fine physical details like armor plating, fabric folds, and muscle definition.
*NOTE* If your Agrax Earthshade accidentally dries with a shiny or glossy sheen, it is typically because the matting agent has settled heavily at the bottom of the bottle. To fix this, use a toothpick to loosen the residue at the base, shake the pot thoroughly for at least a full minute (adding a mixing ball helps), and apply a thin layer of the properly mixed wash over the model. Alternatively, you can coat it with a matte varnish.