Answer:

MAGMA

Answer	Crossword Clue
MAGMA	Hot stuff. underground
MAGMA	Pink Floyd album displayed without any hesitation for French prog rockers (5)
MAGMA	Hard rock it's not

MAGMA	Igneous rocks, once
MAGMA	It becomes igneous rock
MAGMA	Soft rock?
MAGMA	Molten rock
MAGMA	What igneous rock used to be
MAGMA	Lava below the surface
MAGMA	Volcanic fluid
MAGMA	Subsurface material

MAGMA	Mantle piece?
MAGMA	It forms igneous rock
MAGMA	Hot flower?
MAGMA	Igneous rock source
MAGMA	Igneous rock, originally
MAGMA	Molten igneous rock
MAGMA	Molten material
MAGMA	Subterranean hot stuff

MAGMA	Lava, while underground
MAGMA	Piping hot stuff
MAGMA	Hot rock
MAGMA	Lava's precursor
MAGMA	Basalt's beginning
MAGMA	Molten rock beneath Earth's surface
MAGMA	Igneous rock, once
MAGMA	Underground molten rock

MAGMA	Volcanic material
MAGMA	Volcanic outflow
MAGMA	It's under the crust
MAGMA	Lava source
MAGMA	Molten material that becomes igneous rock
MAGMA	Source of igneous rock
MAGMA	Molten rock.
MAGMA	In geology, molten rock.

MAGMA	Mineral mixture.
MAGMA	Source of igneous rock.
MAGMA	Lava's cousin
MAGMA	Igneous-rock producer
MAGMA	Molten rock in the earth