The design that this coin represents is known as “rat face”. This famous design is by Tomás Francisco Prieto, who can be considered the most relevant engraver and medallist in Spanish history. This design appeared in Spanish gold coins minted in America from 1762 to 1772.
Rat face coins were minted in Santa Fe de Nuevo Reino from 1762 to 1771. Most of them were 8 escudos, but they also minted a few 4 escudos and 2 escudos (very few specimens of 2 and 4 escudos coins arrived to our days). During those years, the essayers of Santa Fe de Nuevo Reino were Victoriano del Valle and Juan de Chávez. Both of them printed their essayer mark in the coins (“V” and “J”, respectively). However, in 1769 most of the coins only had the “V” mark. According to some authors only 2 specimens are known to exist with a “JV” mark, although I know up to three specimens to exist.
A very well known Spanish coin dealer told me once that if he could suggest one type of coin to collect, this type would be 8 escudos “rat face”. This simple anecdote shows how commercial these coins are. In fact, their prices increased a lot in the last few years and they can currently be considered the most demanded coins from Spanish colonies.
Regarding the coin in the auction, I know three specimens that appeared in public auctions during the last decades: the one now in the auction was auctioned in 2002 for 46.000 CHF; an UNC specimen was auctioned for 22.000 eurosin March 2012 by Áureo & Calicó; and another specimen in lower grade was auctioned for 16.000 euros in October 2014. Hence, I consider that a reasonable price for this coin can be $30.000 to $40.000, although the previous price of this same specimen shows how expensive a good and extremely rare 8 escudos “rat face” can get.
Description from the seller
Magnificent 1769-JV 8 Escudos Rarity
COLOMBIA. 1769-JV 8 Escudos. Santa Fe de Nuevo Reino (Bogotá) mint. Carlos III (1759-1788). Restrepo M71.14. UNC Detail — Cleaned (PCGS).
One of the outstanding rarities of the Santa Fe onza series, the 1769 issue with assayer JV is thought to be represented by just two surviving specimens. The other variety of this date, with assayer V, is also quite rare. This piece is Uncirculated and boldly lustrous, with full frosty cartwheel luster on both sides and frosty medium yellow gold color. The strike is sharp, trivially misaligned to the top such that no denticles are visible from 9:00 to 12:00 on the obverse and 11:00 to 3:00 on the reverse. Arc die cracks are seen through CAROLUS, and more subtle cracks are present near the mintmark and other peripheral elements at the bottom of the reverse. The visual appeal is absolutely superb, with a highly original appearance despite the presence of horizontal hairlines across the portrait and into the right obverse field that have removed none of the luster or original surface. This date is listed in the Calicó Onza book as “only a few specimens known,” “two known” in Restrepo, and “rarisima” in the March 2002 NAC sale, where this coin brought CHF 46,000.
From the Eldorado Collection of Colombian and Ecuadorian Coins.From Numismatica Ars Classica’s Auction 22, March 2002, lot 277.