ἡ κέρκος τῇ ἀλώπεκι μαρτυρεῖ → you can tell a fox by its tail, small traits give the clue to the character of a person
subs.
P. λίθος Ἡρακλεία, ἡ (Plat., Ion, 533D), λίθος Ἡρακλεῶτις, ἡ (Plat., Ion, 535E), V. Μαγνῆτις λίθος, ἡ (Eur., Frag.), Λυδία λίθος, ἡ (Soph., Frag.).