Ƙananan gilashin ƙarfe shine gilashin tsabta mai tsabta wanda aka yi daga silica da ƙananan ƙarfe. Yana da ƙananan abun ciki na ƙarfe wanda ke kawar da launin shuɗi-kore, musamman a kan girma, gilashin kauri. Irin wannan gilashin yawanci yana da abun ciki na baƙin ƙarfe oxide kusan 0.01%, idan aka kwatanta da kusan sau 10 abun ciki na baƙin ƙarfe na gilashin lebur na yau da kullun. Saboda ƙarancin abun ciki na baƙin ƙarfe, ƙaramin gilashin ƙarfe yana ba da haske mafi girma, yana mai da shi manufa don aikace-aikacen da ke buƙatar tsabta, kamar akwatin kifaye, abubuwan nuni, wasu tagogi, da shawan gilashin da ba su da firam.