WordNet sense 1 (abounding in rocks or stones):

rocky, bouldered, bouldery

WordNet sense 2 (having or caused by an irregular surface):

rough, unsmooth

WordNet sense 3 (showing unfeeling resistance to tender feelings):

flinty, granitic, obdurate

WordNet sense 4 (lacking in feeling or pity or warmth):

hardhearted, heartless

WordNet sense 5 (hard as granite):

granitelike, rocklike

WordNet sense 6 (resisting weight or pressure):

hard