I think Aguest got it right.
Everything leads to Palermo, 1756. Compare with the hallmark of this Eucharistic casehttps://www.beweb.chiesacattolica.it/be ... caristica#
For convenience I have placed side by side the marks of the case with yours.
I have not identified the "G dot T star" mark, but at that time in Palermo there are several silversmith's marks with the final star.