Sedimentary rocks give a geologic history lesson with their layers. For example: sand made from quartz forms into sandstone; clay minerals compress into shale. Igneous rocks are made from once hot ...

Plastistones, a new type of sedimentary rock that’s part-plastic and part-rock, has been found on at least five continents and 11 countries. These rocks form when molten plastic cools within a ...

Rock Types: Igneous, Sedimentary, and Metamorphic Rocks Explained. Posted: March 12, 2025 | Last updated: March 12, 2025. This 1930s educational film explores the natural landscapes, geological ...