પથરમાં પગેરું શું.

patharamāṁ pagēruṁ śuṁ.

Literally: What footprint is there on stone?
What it means: It is impossible to find clues or evidence when dealing with a stubborn, unyielding, or silent person.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) · read from the scan by machine — the Gujarati itself is unchecked · English is machine-made and nobody has checked it yet

Heard it differently, or know we've got the sense wrong? Tell us — that is exactly the kind of correction this needs.