What is "shiazo"

Shiazo (also known as Steam-Stones) is a substitute for hookah tobacco developed in Germany. It consists of a porous mineral which soaks up vegetable glycerol and flavors to generate vapor rather than smoke, which is similar to how electronic cigarettes work. The vapor is usually highly flavored.

Shiazo is supposed to be a healthier alternative to smoking and may be used inside public buildings even after the smoking ban in the European Union, United Kingdom in particular.