Ferric Chloride 1 % is a solution used in histology as an oxidizing agent or mordant. It is often used to prepare tissue preparations for staining with various dyes, such as Perl's Prussian Blue stain. In Perl's staining, the iron(III) chloride solution is used to reveal iron deposits in tissues, which then become visible as a blue-black stain. The 1% iron(III) chloride solution is an important component in histological examination to identify certain tissue characteristics or pathological changes.