Anvils give off a falling dust particles

if an anvil has nothing underneath and isnt falling, it gives a particle like sand/gravel would

 

How to reproduce:

in repeating command blocks, run these two commands:

setblock ~ ~10 ~ minecraft:anvil

execute as @e[type=falling_block] at @s run data modify entity @s Time set value 0

then simply watch the anvil an you will start to eventually see particles