What distinguishes a gum eraser?

A gum eraser is primarily distinguished by its unique texture and composition, which generally leads it to crumble easily when in use. This crumbliness allows it to lift graphite and other pencil marks effectively without smudging, making it ideal for correcting pencil drawings and sketches.

While options such as durability and firmness may suggest certain qualities of an eraser, a gum eraser is recognized more for its ability to break down as it is used, rather than maintaining a steady structure. It is specifically designed to gently erase, which is particularly beneficial for artists aiming to maintain the integrity of their sketches.

In contrast, the other descriptions do not accurately capture the primary characteristic of a gum eraser. It is not specifically intended for sketching (as it can be used for more general purposes), it does not feature oil-based components, and although some erasers may be durable, the hallmark of a gum eraser is its ability to crumble during use.