Igneous Rocks form by some of the most interesting methods of all rocks on Earth. Kids love the varied colors, textures and properties of our igneous rock samples. Each igneous rock sample is individually packaged and comes with an information card to tell you about your new rock. Please note that we always try to have the largest samples possible, but are at times limited by the mines. Typical samples sizes are generally 1-2 inches in length or width but can vary based in availability and natural formation.