1. Intrusive--Magma
   1. Granite
      1. Topic
2. Extrusive--Lava
   1. Obsidian
      1. Topic
         1. Topic
   2. Pumice
      1. Topic
         1. Topic
   3. Basalt
      1. Topic
         1. Topic
            1. Topic
   4. Porphyritic
      1. Topic
         1. Topic
3. Topic
4. cools slowly-forms crystals
5. Cools quickly-fewer crystals
6. coarse grained
7. Glassy
8. Fine grained
9. Fine and coarse grained