Methods and systems for rock recognition are provided. In one embodiment, a method comprises: receiving or generating, at one or more computing systems, data comprising at least one drilling variable for a plurality of drilled holes across observations at a plurality of depths, wherein the at least one drilling variable is a variable affected by at least one physical characteristic of rock in the plurality of drilled holes; determining, by the one or more computing systems, a plurality of characteristic measures for each of the plurality of drilled holes, wherein the plurality of characteristic measures for each drilled hole comprise: at least one characteristic measure of a first type, wherein a characteristic measure of the first type is a measure based on a comparison of a distribution of a said at least one drilling variable for the drill hole with a distribution of a related or the same drilling variable across a plurality of the drilled holes; and at least one characteristic measure of a second type, wherein a characteristic measure of the second type is based on said at least one drilling variable across the plurality of depths of the drilled hole; applying, by the one or more computing systems, unsupervised learning to the plurality of characteristic measures, the unsupervised learning determining groups of the drilled holes; and generating, by the one or more computing systems, an output indicating the determined groups of the drilled holes.