This website guides the student through the basic igneous rock types and introduces them to a rudimentary classification scheme. This particular topic in Earth Science presents many difficulties for the on-line teaching environment, since rock identification is a process traditionally taught by hands-on interaction with the rock materials themselves. Overall the site does accomplish the goal of offering a very basic introduction to igneous rocks. I would recommend its use as a supplemental material for a laboratory course, and that is the context in which I plan to use it this summer. I may supplement my comments after testing it on my class, so look for an update.
. Rocks are notoriously difficult to photograph in a way meaningful to the identification process, and Perry has handled this problem very well. The photo quality is generally very good and the photos selected demonstrate the intended characteristics. Photo hand samples can also be enlarged for better viewing. Field views of the rocks being discussed are also included where appropriate. The site is simple straight forward, easy to navigate, and does a credible job of recreating the laboratory identification process.