On the microscopic distinction of zirconium and hafnium

A method has been worked out for the microscopic distinction of zirconium and hafnium by means of the reagent of MARTINI, quinoline and ammonium thiocyanate. When using this reaction exactly as described by MARTINI, there generally is a difference in the shape of the primarily formed crystals. When using 25% formic acid as a solvent instead of HCl 1:2, hafnium, always gives a good reaction, whereas the zirconium reaction is prevented.