The materioptikon comes from
the Sandman graphic novels, by
Neil Gaiman.
The ruby that is one of Dream's symbols of office, along with his helm and bag of sand. The humans who steal the ruby from him in Preludes and Nocturnes betray each other and it gets lost in the shuffle, ending up in a JLA warehouse. Its power to bend and shape dreams and reality is shown later in the same book; John Dee says that
"the ruby seems to turn (dreams) into matter It forces them to translate themselves into forms we can recognize in this world. It also controls dreams in their raw state: your dreams. Anybody's dreams. ... It isn't a ruby, really. It's a solid dream."
Morpheus gradually reclaims all of his tools and comes back into power in the
Realm of Dreams.