Let me introduce, — this stone is Sepia officinalis, a common cuttlefish: the Cephalopodic master of camouflage, that is abled to change it's own colour and to pour others with noble ink, the ten-armed predator, the possessor of wonderful eyes even more perfect than an octopus has.
In fact, these eyes is the only thing that makes cuttlefish recognizible in environment.