Igneous Rock is formed by the solidification of molten magma.
This Lava Rock is an igneous rock. It's location is unknown, but since it's lava rock, it's found mostly around inactive/active volcanic areas. This rock could be of Scoria in nature. The vesicles are of trapped gas.
The reason you call tell it's a Igneous rock is by the texture. The rock is uniformed without layers.
Marine Sedimentary rocks are formed from consolidated clay sediments.
This rock is a sedimentary rock. It's location is unknown. When I received this rock many years ago it was said it came from a town called Coalinga, CA. The town is situated about 100 miles east of the ocean. Upon further research the area of Coalinga use to be an ancient sea bed. So, the possibility it came from Coalinga, Ca, can be true.
The reason you can tell it's a sedimentary rock is by the texture of it. Mostly, all sedimentary rocks have layers or strata. Sedimentary rocks can sometimes collect various organisms bones or shells that undergo some recrystallization in ground water. This becomes a fossil.
Metamorphic rocks are rocks that are altered by pressure and heat.
This metamorphic rock was found near the ocean.
The reason you can tell it's a metamorphic rock is by the texture, but that really doesn't help that much either. Metamorphic is very similar to igneous rock, so you have to look closely and examine all the detail of it.