The cornerstone is the stone that lies at the corner of two walls and forms part of the foundation of an edifice. In Masonic buildings, it is now always placed in the northeast; but this rule was not always formally observed. The symbolism of the corner stone when duly laid with Masonic rites is full of significance, which refers to its form, to its situation, to its permanence, and to its consecration. As to form, it must be perfectly square on its surfaces, and its solid contents a cube. The square is a symbol of morality, and the cube of truth. The situation at the corner of the north and east, the north representing darkness and the east representing light, presents the symbol of Masonic progress from darkness to light, and from ignorance to knowledge. The cornerstone is supposed to be of a more permanent and durable quality than any other part of the building, lasting beyond the decay and ruin of the building, and therefore, reminding the Mason that when his earthly Tabernacle of his life shall have passed away, he has within him, a sure foundation of eternal life. In Masonic symbolism, it signifies a true Mason, and therefore it is the first character which the Apprentice is made to represent after his initiation has been completed.