Linked from
The 35 pages that link to Igneous rock, each with the reason it gives.
Canadian ShieldRelated: Much Shield bedrock crystallized from ancient magma.
Rock cycleRelated: Cooling magma or lava creates the igneous rocks that begin many cycle pathways.
ProtolithRelated: Igneous rocks can become protoliths for metamorphic rocks.
BiotiteRelated: Biotite occurs in many granites and other intermediate to felsic igneous rocks.
SpinelRelated: Spinel also occurs in some igneous rocks and their mantle-derived inclusions.