“Athanor comes from the Arabic word "al-tannur" (oven), the athanor is the furnace used by the alchemists to perfect matter. Built of brick or clay, the athanor usually was shaped like a tower with a domed roof and was designed to keep an even heat over long periods of time. The alchemists considered it an incubator and sometimes referred to it as the "House of the Chick." Symbolically, the athanor is also the human body and the fire of bodily metabolism that fuels our transformation and the ultimate creation of a Second Body of light. The mountain is a symbol for the athanor, since the perfection of the metals takes place under the guise of Nature within mountains. Sometimes a hollow oak tree is used to symbolize the athanor.”
- Alchemy Reference Guide: A Tool for Exploring the Secret Art, Dennis William Hauck