Single crystals of potassium nitrate with prismatic morphology were gr
own in silica gel at room temperature in the range pH 3-4 by the solub
ility reduction process. Methyl acetate was used as the supernatant li
quid. Chemical etching, hardness studies and thermal analysis were car
ried out on these crystals. Indentation observations revealed strong a
nisotropy of the material. The material was found to be thermally stab
le up to 598 K.