Postby blakstone » Fri Jan 10, 2014 2:10 am
There are two other bits of information that can be gleaned from the marks.
First, at this time, Geneva had three silver standards: the first of 11 deniers (.913), which were marked with the warden's mark and the maker's mark, 10 deniers (.833), which were marked with the warden's mark and the maker's mark struck twice, and the third of 9 deniers (.750), which were marked with the maker's mark only (i.e., no warden's mark). Your piece corresponds to the first of these, and is therefore presumably .917 fine.
Second, the Geneva warden's jury comprised three members, with a new warden elected each year for a term of three years. Their terms were therefore staggered, and while it is not known whether they each used their own mark or whether they all used the mark of the senior warden, logic dictates that any given warden's mark can only have been used during his tenure. Antoine Renaud served as warden 1785-1787, thus presumably limiting the date of your piece to those years.
Hope this helps!
Ref: Pierre-François de Vevey, Manuel des Orfèvres de Suisse Romande (Fribourg: Sotheby’s Office du Livre, 1985), pp. 54-56.