I pick one up and turn it around in my fingers, weight it in the palm of my hand.  If it is wood, chestnut or elm, it is even lighter than the ivory.  You see the patina more easily on these wooden ones: there is a faint shine on the spine of the bridled wolf and on the tumbling acrobats locked in their embrace.  The ivory ones come in shades of cream, every color, in fact, but white.  A few have inland eyes of amber or horn.  Some of the older ones are slightly worn away: the haunch of the faun resting on leaves has lost its markings.  There is a slight split, an almost imperceptible fault line on the cicada.  Who dropped it? Where and when?