from The Century Dictionary and Cyclopedia
- n. A polished quartz crystal serving as a magic mirror in certain incantations.
Sorry, no etymologies found.
The learned professor thought that witchcraft might be proved by witnesses who have heard the accused person invoking the devil for help, or seen the suspected party entertaining a familiar spirit and feeding it in any form or likeness, conjuring to raise storms, showing in a glass or show-stone the faces of absent persons.
His show-stone or mirror is still preserved among other curiosities in the British Museum.