friable
adjective
°Easily broken into small fragments, crumbled, or reduced to powder.
"1977: Spiders had woven their vague trapezes between the friable heads of dead peonies in enormous glass jars streaked with tide marks where the water had evaporated long ago. — Angela Carter, The Passion of New Eve"
°(of soil) Loose and large-grained in consistency.
synonyms: crumbly