igneous

Everyday

1. Igneous rock is rock formed when hot melted rock (magma or lava) cools and becomes hard. tree →
2. Igneous can describe anything to do with fire or volcanoes (rare). tree →

In the lessons

In science (geology) it is one of the three main kinds of rock: igneous, sedimentary and metamorphic. Pupils learn that granite and basalt are igneous and that fast cooling gives small crystals, slow cooling gives big crystals. Phrases: igneous rock, extrusive/intrusive igneous rock.

Examples

• Granite is an igneous rock. tree →
• Igneous rocks form from cooled lava or magma. tree →
• Basalt is a dark igneous rock from volcanoes. tree →
• Pumice is an igneous rock so light it can float. tree →
• We sorted our rocks into igneous, sedimentary and metamorphic. tree →
• Igneous rock that cools slowly underground has large crystals. tree →
• The volcano left a layer of igneous rock. tree →
• Is obsidian igneous? Yes, it is volcanic glass. tree →

Note

Starts with a vowel: "an igneous rock". Pronounced IG-nee-us. Comes from Latin "ignis" = fire (like "ignite"). Not used for people. Myth: not all igneous rock comes from volcanoes above ground; some cools deep underground.