This paper presents the archaeology of enigmatic signs printed on the bases of 18th and 19th century crucibles recovered from excavations at the Brazilian Mint in Rio de Janeiro during the 1980s; as well as the explanation of their symbolic meaning in the light of alchemy, occultism and Freemasonry. Spreading extraordinarily around the world through a well succeeded strategy of visual communication, the Freemasonry made use of hermetic symbols printed and/or attached to different supports with the purpose of diffusing its principles. We are, apparently, before a sign of Masonic recognition, the external sign of an occult organization, exclusively shared by the initiated and in turn incomprehensible for the rest. This contributed to the diffusion of the Freemasonry doctrine to different points of the world, always in a cloaked manner.
Crucible; Alchemy; Freemasonry