Heritage Auctions had an 1818 1/2 Real which sold for $44 back in '96, from Zacatecas. Unfortunately, there is no photo of it. Here's the caption from HA:
Ferdinand VII 1/2 Real 1818 Z.-M.A.G. unlisted by Krause but listed as Calico 1253. Decent detail for the type and rare. VG/F.
With the data provided on this thread, now I know there are 3 varieties of this 1/2 Real from Zacatecas (1811-1812, 1813-1819, 1820-1821), and that the lettering on the reverse of George's coin for the middle variety (IND R. Z. M. A. G.) is a true Real for that date.
So it looks like the "Onza Main Book 1611 – 1873", written by the Calico brothers, 1986, may contain a better pic of this coin.
I would love to see a pic of another besides George's between 1813-1819. Looks to be a rather rare coin for lack of a good pic somewhere on the Net.
HH,
CAPTN SE
Dan