A craftable and “makeable“ cement block.
Method 1: Craft wet cement blocks by putting default:gravel, group:sand, and bucket:bucket_water in a shapeless recipe.
Method 2: Make dry cement blocks by putting default:gravel and group:sand in a shapeless recipe and put the resulting node on ground directly by a water source to get a wet cement block and wait till it becomes wet.
Place wet cement blocks wherever you want (no water in neighboring nodes) and let them become hard. Since dry and wet cement blocks fall down when placed you might want to support them while drying by placing a not falling node below.
Hard cement blocks floats like regular nodes.