What is the symbolic significance of the rough and perfect ashlars in Craft Masonry?

The rough ashlar represents the uncultivated mind in an untrained state, while the perfect ashlar signifies the mature mind refined by instruction, virtue, and experience 2. Positioned as immovable jewels open for contemplation 2, the two stones symbolise the moral and intellectual journey toward enlightenment, as an article on the United Grand Lodge of England's website observes. An article on the Grand Lodge of India's website notes that the rough ashlar is assigned to the Entered Apprentice to work upon, whereas the perfect ashlar belongs to the Fellow Craft to try and adjust his tools.

Early monitorial catechisms describe the rough stone from the quarry as being brought into due form through education, rendering the individual a fit member of society 2. The perfect ashlar, cut to a true die square, represents the mind after a well-spent life of devotion, tested by conscience and divine rule 2. W. L. Wilmshurst expands this into a spiritual allegory, holding that a candidate enters in a state of rough ignorance and must develop his character into a finished cube 1. He compares the chipping and polishing of stone to the toil, self-scrutiny, and adversity required to perfect human nature 1.

Historical lodge lectures were not always uniform on the distinction. Arthur Edward Waite notes that eighteenth-century lectures differed on how the stones were categorized among the immovable jewels, leading later Masonic scholars such as George Oliver and Albert Mackey to debate whether early terms like the broached thurnel referred to the rough or perfect ashlar 3.