From Longman Dictionary of Contemporary Englishfriablefri‧a‧ble /ˈfraɪəbəl/ adjective technical HEGfriable rocks or soil are easily broken into very small pieces or into powder
Examples from the Corpus
friable• The end product is of similar appearance to peat, rich and dark in colour and friable.• The soil was dark and friable between her fingers.• Andy leads off up large, friable flakes, hair plastered to his head but now mercifully sheltered.• It is best to avoid cutting soft or friable rocks such as shales, evaporites, coals and chalks on a lubricated saw.• Sunlight smashed into me as I pulled on to the top of a little pinnacle below a very steep, friable slab.• Bananas like a rich, friable soil and plenty of water.Origin friable (1500-1600) French Latin friare “to break into very small pieces” 