* Igneous rocks form from the cooling and solidification of magma (molten rock) or lava. This is a broad category that includes rocks formed both above and below the Earth's surface.

* Volcanic rocks specifically form from the cooling and solidification of lava on the Earth's surface.

Therefore, all volcanic rocks are igneous, but not all igneous rocks are volcanic.

Here's a breakdown:

* Volcanic rocks are a subset of igneous rocks.

* Intrusive igneous rocks form from magma that cools and solidifies within the Earth's crust (examples: granite, gabbro). These are not volcanic.

* Extrusive igneous rocks form from lava that cools and solidifies on the Earth's surface (examples: basalt, rhyolite). These are volcanic.

So, while all volcanic rocks are igneous, many igneous rocks are not volcanic.