"The Quarry" is the name of the mural left by the artist Mariana Duarte Santos in Campo, the parish that still hosts the Empresa das Lousas de Valongo, turning this Black Stone into a symbol of the region.

The photograph that inspired the work, which can be found at the Slate Museum, dates back to 1926 and portrays the harshness of the labor to which many men and women of Valongo dedicated themselves, to whom this symbolic tribute is dedicated.