For each key characteristic, list whether it is found in sedimentary, igneous, or metamorphic rock:
• fossils:
• crystals:
• gas bubbles:
• glassy surface:
• foliation:
• sand or pebbles:

Fossils: preserved remains of a living thing (mostly found in sedimentary rocks)
Crystals: a piece of a solid substance having a natural geometrical form ( found in igneous rocks and sedimentary (mostly igneous))
Gas bubbles: (igneous) made in a rock by eruptions or volcanoes
Glassy surface: of a rock looks like a block of glass (colored) also sometimes occurs because of volcanoes (igneous)
Foliation: (metamorphic rocks) layering in rocks; can be thin layering or thick
Sand or pebbles: (sedimentary) Sand: mineral particles of a rock Pebbles: a coast of a rock usually smooth