Refers to the Earth's mantle, the layer between the crust and the core.
The Earth's mantle is mostly made of solid rock.
gas mantle
A mesh cover placed over a gas flame to produce bright light; often used in camping lanterns.
See also: ガスマントル
I attached a new mantle to the camping lantern.
When temperatures rise, part of the mantle melts and becomes magma.
The lantern's light had grown dim, so I replaced the mantle.