flinty
flin-ty
adjective
Resembling flint; very hard, grey, and stony in texture.
"The flinty soil was hard to dig."
adjective
Showing a stern, unyielding, or harsh character or expression.
"He gave her a flinty stare."
Thesaurus
Synonyms: flint, obdurate, granitic, hardhearted, heartless, stony