This electronic text is a personal essay on the Nature of Volcanic Rocks as expressed through their geologic context, texture, and mineralogy. In the scheme described in the text, rocks are not identified by name. Rather, they are characterized by their mineralogy. I view what I’ve written as my personal expression of a summary for a short course on volcanic rocks. I hope a reader who wants to know about volcanic rocks rather than how to name them will find something here. Working through the Nature of Volcanic Rocks will not make one an accomplished volcanic petrologist, but I do hope it will put such people on a track to the information they need to better assess accounts of volcanic events when such accounts appear in the daily news.