50 specimens approximately 1-1/2". Includes industrial minerals, gem-type minerals, rock-forming minerals and igneous, sedimentary and metamorphic rocks plus Study Guide. Grades 5-12. Ages 10-18. 50 specimens approximately 1-1/2". Includes industrial minerals, gem-type minerals, rock-forming minerals and igneous, sedimentary and metamorphic rocks plus Study Guide. Grades 5-12. Ages 10-18.