well... you guys got me worried about my liquid crystal deodorant so done some searching... would appreciate feed back on the following --
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DSA's deodorant stones are made of potassium alum. It is a pure product made without the addition of chemicals, fragrances, oils or alcohol. The chemical formula for potassium alum is K2SO4Al2(SO4)324H20. Potassium alum is a colorless substance that forms octahedral or cubic crystals.

Bauxite is the ore from which alum is drawn. It is formed by the rapid weathering of granitic rocks in warm, humid climates and can be purified and converted directly into alum. 

Potassium alum is soluble in seven times its weight of water at oom temperature and is very soluble in hot water. When crystalline potassium alum is heated, some of the water of hydration becomes chemically separated, and the partly dehydrated salt dissolves in this water, so that the alum appears to melt at about 90 degrees C (approx. 392 degrees F), potassium alum swells up, loses all water, and becomes a basic salt called burn alum. Potassium alum has a density of 1.725.

Alum's are used for a variety of uses including as a powerful astringent. 

If an aluminum compound, such as aluminum chlorhydrate or aluminum zirconium, which is very soluble, is used as an antiperspirant, that compound is readily absorbed. Once in the body, the aluminum portion of the molecule ionizes, forming free or radical aluminum (Al+++). This passes freely across cell membranes, and forms a physical plug, that when dissolved is selectively absorbed by the liver, kidney, brain, cartilage and bone marrow. It is this concentration of aluminum that has been the source of concern in the medical community and has prompted the research being done on ALZHEIMER'S DISEASE and BREAST CANCER victims. Potassium alum molecules have a negative ionic charge, making it unable to pass through the cell wall. THEY ARE NOT ABSORBED. This is why our deodorants are safe to use and will not cause high levels of ALUMINUM in your system. ALUM and ALUMINUM are two different substances, with distinct chemical signatures. They possess different chemical properties which create different chemical attributes. 

We hope this information helps to dispel some of the misunderstandings about ALUM and puts your mind at ease about the safety of all of DSA's deodorant products.

http://www.deodorantstones.com/testpage.ivnu