noun / verb
chalk
CHAWK/tʃɔːk/
A soft, usually white material used for writing or marking.
Several sticks of chalk rest on the dark slate surface.

Etymology
The ancestor meaning “small pebble” came to name limestone, then specifically England’s soft white limestone—the material used to make marks. Its deeper origin is uncertain.
In context
there's the bust line so I tried using a different chalk color thinking it would be visible but it was so I'm going over the line again with my white chalk
More examples
- White chalk dust covered his fingers.
- We chalked a starting line across the pavement.
- The children are chalking pictures on the sidewalk.
Forms
chalk · chalks · chalked · chalking