prize9-1, Exercise 3: One rock from each family

Model answer (check the details):

Igneous: granite. Forms when molten rock cools slowly underground, so it has large visible crystals. Tell it apart by the interlocking mix of light and dark crystals and the absence of layers.

Sedimentary: sandstone. Forms when grains of sand are buried and cemented. Tell it apart by the grains you can feel, often in layers, and sometimes fossils or ripple marks.

Metamorphic: slate. Forms when shale is heated and pressed. Tell it apart by the way it splits into thin flat sheets.

Care: follow safety advice and do not collect from protected sites.