Rocks

4. – a fine-grained sedimentary rock formed from compacted clay and mud.
6. – a coarse-grained igneous rock containing feldspar and dark minerals.
9. – a metamorphic rock formed when limestone is subjected to heat and pressure.
11. – a metamorphic rock rich in flaky minerals that give it a layered appearance.
14. – a fine-grained metamorphic rock that splits into thin layers.
15. – a sedimentary rock composed mainly of calcium carbonate.
16. – a sedimentary rock formed from compacted sand grains.
18. – a coarse-grained igneous rock composed mainly of quartz and feldspar.
19. – a hard, fine-grained sedimentary rock composed mainly of silica.
20. – a hard metamorphic rock formed from sandstone.

1. – a combustible sedimentary rock formed from the remains of ancient plants.
2. – a metamorphic rock with distinct light and dark mineral bands.
3. – a sedimentary rock made up of rounded pebbles and gravel cemented together.
5. – a volcanic igneous rock with a composition between basalt and rhyolite.
7. – a dark, fine-grained igneous rock formed from cooled lava.
8. – a light-coloured igneous rock with a high silica content.
10. – a lightweight volcanic rock full of gas bubbles.
12. – a natural volcanic glass formed by the rapid cooling of lava.
13. – a naturally occurring solid mass made up of one or more minerals.
17. – a sedimentary rock composed of angular rock fragments joined by a natural cement.