List of Popular Shewstones

The most common media used for scrying are:

• Crystal balls, crystals, precious stones, polished quartz, or another transparent body; this is called gastromancy (also crystallomancy or spheromancy). Sometimes “crystal gazing” refers specifically to spheromancy. Crystal balls are also called shew stones. A stone or crystal is also called a seerstone or peepstone.
• Water or another liquid; this is called hydromancy.
• Fire known as pyromancy.
• Air or atmospheric conditions known as aeromancy.
• Earth, soil or dirt known as geomancy.
• Mirrors; this is called catoptromancy, also known as captromancy, enoptromancy, or mirror gazing.

Specific objects that have been used for scrying include:

• a pool of ink in the hand (Egypt)
• the liver of an animal (tribes of the North-West Indian frontier)
• a hole filled with water (Polynesia)
• quartz crystals (the Apaches and the Euahlayi tribe of New South Wales)
• a smooth slab of polished black stone (the Huille-che of South America)
• water in a vessel (Zulus and Siberians)
• a crystal (the Incas)
• a mirror (classical Greece and the Middle Ages)
• a fingernail
• a swordblade
• a ring-stone
• a glass of sherry
• the burning of a poppy flowerbud on hot coals

http://en.wikipedia.org/wiki/Shewstone