Fill in the Blanks Complete the sentences.Online version Choose the correct word to complete sentences about rocks and minerals. by Raquel Serrano Barrueta 1 cools large small colour minerals rock crystals materials lava Rocks lava are clusters of and other inorganic . Minerals are structured that have specific chemical components . Igneous rocks form when molten from volcanoes cools down . If the cools quickly , crystals form and the rock has dots of . If the lava slowly , crystals form and the looks the same colour all over . Sedimentary rocks and fossils compact over millions of years . Metamorphic rocks form when igneous and sedimentary rocks are pushed down by other layers of rock from above .