Inorganic in nature, ammonium fluoride possesses a wurtzite crystalline structure, a sharp saline taste, and is highly water soluble. Ammonium fluoride is typically synthesized using a solid-liquid halogen exchange process in which potassium fluoride is directly exposed to corresponding halides. One of the more unique identifying features of ammonium fluoride in its crystalline form is that it resembles ice crystals in its formation, and is the only substance known to produce mixed crystals when dissolved in water. It is usually referred to as commercial ammonium fluoride, or neutral commercial ammonium fluoride to represent its neutral salt form. The acid salt form is preferred in its application for glass etching and related silicates. Due to the acidic nature of ammonium fluoride and its reactivity with silicates, it cannot be handled in glass test tubes or apparatus when used in a laboratory for obvious safety reasons. Further uses include wood preservation, mothproofing, printing and dyeing textiles, and as an antiseptic in breweries.