- Igneous rocks / minerals are formed by magma / lava cooling / crystallizing
- Pumice is a kind of igneous rock
- Hence, pumice is formed by lava cooling

- If something is formed by a material changing then that something is formed from that material
- Lava is a kind of material
- So, if something is formed by lava changing then that something is formed from lava

- If something is formed by lava changing then that something is formed from lava
- Cooling is a kind of change
- Hence, if something is formed by lava cooling then that something is formed from lava

- Pumice is formed by lava cooling
- If something is formed by lava cooling then that something is formed from lava
- Therefore, pumice is formed from lava

- A volcano is a source of magma / lava
- Usually something can be found near a source in greater concentrations
- Hence, usually lava can be found near a volcano

- Usually lava can be found near a volcano
- If something usually happens then that something is likely to happen
- Hence, lava can likely be found near a volcano

- Pumice is formed from lava
- Lava can likely be found near a volcano
- So, pumice is likely formed near a volcano

Therefore, pumice is likely formed near a volcano
[Question]Where is an igneous rock such as pumice most likely formed?
[Context]- If something usually happens then that something is likely to happen 
- Igneous rocks / minerals are formed by magma / lava cooling / crystallizing 
- If something is formed by a material changing then that something is formed from that material 
- A volcano is a source of magma / lava 
- Usually something can be found near a source in greater concentrations 
- Cooling is a kind of change 
- Lava is a kind of material 
- Pumice is a kind of igneous rock