Chisel

The chisel is one of the working tools of an Entered Apprentice, and symbolizes the effects of education on the human mind.   For as the artist, by the aid of his instrument, gives form and regularity to the shapeless mass of stone, so education, by cultivating the ideas and by polishing the rude thoughts, transforms the ignorant savage into the civilized being.  In the English ceremonies, the chisel is one of the working tools of the Entered Apprentice and has the same reference to the advantages of education.  
Preston (Illustrations of Masonry) thus elaborates its symbolism as one of the implements of Freemasonry:  "The chisel demonstrates the advantages of discipline and education.  The mind, like the diamond in its original state, is unpolished; but as the effects of the chisel on the external coat soon present to view the latent beauties of the diamond, so education discovers the latent virtues of the mind and draws them forth to range the large field of matter and space,  in order to display the summit of human knowledge, our duty to God and man."