The addition of quercetin, an organic flavone (C15H 10O7), to aqueous solutions containing silica and aluminum and adjusted to final pH's from 6.5 to 8.5 produced a 1 : 1 aluminosilicate precipitate which, after 6 to 16 months of aging in solution at 25??C, contained as much as 5 percent well-formed kaolinite plates. Similar solutions containing no organic material produced relatively amorphous precipitates with the same composition and stability (standard free energy of formation = - 897 ?? 1 kilocalories per mole) but with substantially smaller amounts of crystalline material even after 2 years of aging.