Other blocks
Concrete Plate Round 13m Right 14
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 (9 POIs)
Shamway Factory (tier 5), The Last Sunset Nursing Home (tier 5), U.S. Army Post #7 (tier 5), Don Vittorio Spagetto Residence (tier 4), Favales Academy (tier 4), Pass-N-Gas Plaza (tier 3), The Serrano Residence (tier 3), Arbor Loop Rest Area, Shady Rest Area.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.