hard as stone
- rockSolid earthen material
- graniteIgneous rock, quartz-rich
- marbleRecrystallized limestone rock
- solidFirm matter state
- unyieldingRefusing to give way
rigid · firm · flint · concrete · boulder · cold · unforgiving · stubborn · immovable · petrified · fossilized · diamond · iron · steel · dense · compact · unbreakable · jaw
physical texture/firmness
hard as stonesoft as butter
soft as silk · malleable · spongy · pliable · yielding
emotional quality
hard as stonesoft-hearted
Readily feeling sympathy
tender-hearted · warm-hearted · compassionate · gentle · sensitive
difficulty/ease
hard as stoneeasy as pie
Extremely simple to accomplish
piece of cake · child's play · effortless · simple · straightforward