The little data we have about Garzoni's life are the brief notices registered on official documents of the Society of Jesus.
Garzoni's only extant work, the Due trattati sopra la natura, e le qualità della calamita, is the first known example of a modern treatment of magnetic phenomena.
Even if the Jesuit is never mentioned, both Della Porta's Magia Naturalis (1589) and Gilbert's De Magnete (1600) shows a heavy dependence on Garzoni's treatise.
Firstly, the author ascertains that the motion towards the poles is a natural one, ascribes it to an internal mover ant its appropriate instrument, which he names the qualità delle due facce (quality of two faces).
The most interesting features concerns Garzoni's description of the way verticity moves the loadstone and the way it alters surrounding bodies, virtually propagating itself outside the stone.
The configuration Garzoni obtains coincides with the one theorized in the first treatise (look at the accompanying diagrams displaying the lines of propagation of verticity).