Igneous rock at the Earth's surface that is weathered and wears away is still called igneous rock. Weathering and erosion don't change the rock's fundamental composition, just its size, shape, and sometimes its mineral composition.

Here's a breakdown:

* Igneous rock: Formed from the cooling and solidification of magma or lava.

* Weathering: The process of breaking down rocks, soils, and minerals through contact with the Earth's atmosphere, water, and biological organisms.

* Erosion: The process of moving weathered material from one place to another, often by wind, water, or ice.

So, a granite boulder exposed to the elements might undergo weathering and erosion, becoming smaller, rounder, and covered in lichens. But it's still fundamentally granite, an igneous rock.