Decor and furniture
Parking Block Broken Blue
A composite material composed of sand, stone, and cement. This block can not be upgraded and is likely only found in the creative menu.
Harvest drops
Small Stone× 25
Taken apart with a harvesting tool (axe, pickaxe, shovel), before perks and tool bonuses.
When it collapses
Falling, it leaves 
Destroyed Stone (75% of the time) where it lands.
Where to find (7 POIs)
Champions Coliseum (tier 5), Wasted Stiff's (tier 4), NPD 3rd Division (tier 3), Post Office #2 (tier 3), Blue Birdie (tier 1), The Book Barn (tier 1), Pristine Healthcare.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.