Tags: Chemical Substance, Mineral.
Buddingtonite is an ammonium feldspar with formula: NH4AlSi3O8 (note: some sources add 0.5H2O to the formula). It forms in hydrothermal areas by alteration of primary feldspar minerals. It is an indicator of possible gold and silver deposits as they can become concentrated by hydrothermal processes. It crystallizes in the monoclinic crystal system and is colorless to white with a vitreous luster. Its structure is analogous to that of high sanidine (KAlSi3O8).