Madrid minted 8 escudo coins under the name of Philip V for the last time in 1730. Very low quantities of 8 escudos were produced that year. In addition, a new assayer came to Madrid and, for the first time, the initial letter of his surname appeared on these coins. He was Fernando Vázquez (the “F” is his initial) who was an assayer in Segovia since 1728. He came to Madrid in 1730 as a second assayer and remained there until he died in 1742. The first assayer was Juan Joseph Caballero (“J”), son of another assayer of the same name, who came from Cuenca to Madrid in 1728, and became the most important assayer of the Kingdom. You can find more details about these assayers and Madrid mint in this book from Glenn Murray.
This coin is not properly described in the Calicó and the Krause catalogues, as they describe it with JJ assayers. The 8 escudos Madrid 1730 JJ does not exist. Only three specimens of this coin were known in 2005, although we can now count four: one not sold for 10.000 in 2005; another one sold for 10.000 in 2014; and another one in very high condition which was hammered last June for 40.000 euros, and was previously hammered in 2011 for 17.000 euros (see lot 171).
The quality of this coin makes it not to be very good for the collectors that are not specialized in Spanish ounces. However, it is typical for those specialized collectors who look for all the variations of design, mint and assayers, making it a very difficult coin to obtain, as it is the only ounce from Madrid depicting JF assayers. Furthermore, only one coin in higher grade is known to exist. My opinion is that 10.000 to 12.000 euros is a fair hammer price for this coin.
Description from the seller
8 Escudos. 1730. MADRID. J.F. 27,02 grs. Sin indicación de valor. El catálogo Calicó sólo cita esta fecha con ensayadores J.J. El catálogo de la Onza (XC) indica pocos ejemplares conocidos. Última Onza de Felipe V de esta ceca. Las siglas J. F. pertenecen a José García Caballero y a Fernando Vázquez que llegaron a acuñar juntos en el año 1730 en la ceca de Madrid. Restos de brillo. RARÍSIMA. Cal-No cat.; XC-376. EBC-.