Whetstone Mountain is a 12,527-foot summit in western Colorado near Crested Butte, notable as a prominent laccolith in the West Elk Mountains. Formed about 30 million years ago when magma intruded into sedimentary rock, it was later exposed as erosion removed softer layers and revealed its igneous core. Its bedrock includes quartz monzonite porphyry and granodiorite porphyry, and glaciation further shaped the peak, especially on its north side. The name came from stone collected there by the Hayden Survey in the early 1870s; an earlier recorded form was Wheatstone Mountain before Whetstone Mountain was established in 1927. Today it stands out for both elevation and geologic significance.