'Igneous rock' presents a pleasing contradiction for the novelist Sarah Moss. Fire rock, flaming stone. "At the centre of everything" she says "is stone, is liquid, is flame, elements out of their element." In this essay, Sarah explores the nature of the igneous. She's drawn to basalt and dolerite, the fire rocks that created Antrim's Giant's Causeway and Lindisfarne in Northumberland.

This is the fourth of this week's series of essays in which writers reflect on landscapes that matter to them, shaped and underpinned as they are by their geology.

Sarah has lived in Iceland, a place she recalls being as if liquid rock "had frozen in movement and then been haphazardly covered with turf and birch and rowan". Her latest novel is 'The Tidal Zone'.

Producer: Mark Smalley. Show less