it has to much lines
The fracturing of rock along curved lines that results when pressure is removed from bedrock is called fracking.
sandstone is a sedimentary rock because of the layers or lines you can see on it
if it is sedimentary by lines all over it
Weather and erosion only mark a rock. They leave lines /patterns and eventualy work into it.
Chalk is a hard rock, with large lines of weakness so will erode by physical weathering and the sea.