Collection Of 20 Rocks, 1 Each

The United Scientific® Collection of 20 Rocks is a boxed earth science set of 20 rock specimens covering igneous, sedimentary and metamorphic types, from basalt and obsidian to marble, slate, flint and shale. Specimens average 2 x 3 x 1.5 cm, and a specimen key inside the box identifies each one. Teachers use it for rock identification practice and rock cycle lessons in middle and high school classes.