This is a Potosi mint one real (clipped), E assayer, (Elgueta o Ergueta). I can barely see the tops of the date on the obverse of the coin (Pillar and Wave side), but it appears to me as 1665. Usually, only the last two digits of the date are seen on Pillar and Waves type cobs, (Obverse and Reverse) so if you look below the VI on the obverse side (which is actually UL, and part of the legend "Plus Ultra") you can see the extreme tops of two digits (65). 1665 is the correct time frame for "E" Assayer at the Potosi mint. The left half of the "E" Assayer mark can be seen at the one o'clock position which would be to the right of the Pillar on the obverse. The extreme lower right of the 1 (indicating denomination) can be seen at the 12 o'clock position of the obverse and to the left of the Pillar. The castle variant visible on the reverse is also known to this era. Refer to Sellschopp, "Coinage of Peru", page182
Trez, your guess is well taken, although, "F" assayer struck only eight reales in 1697 (Sellschopp, page 192.) Assayers were paid according to the weight of their production, so striking eight reales was infinitely more profitable. Other than that, their is no know explanation why "F" assayer did not strike one reals in 1697, but this being historically known absolutely rules out assayer "F". The number 5 was carved onto coin dies differently in the 1600s compared to what we are used to seeing today. With the extreme angle on the top portion of the second digit, I'll have to stick with my opinion that this cob is an "E" assayer, 1665. I'll have to say though, that there isn't much for us to look at on this cob, and there is room for some speculation, but it is unquestionable that this piece is certainly a late 1600s period Carlos II Potosi mint cob one real, making both of us correct in our assumptions. When I left Treasure Salvor's Inc in Key West FLA, I worked for Conch Coin Company (a couple blocks away from the Mel Fisher museum.) With the hundreds of Cob coins I personally certified, I think "E" was the most common assayer I found on the Pillar and Wave Potosi cobs. "F" was less common to find as he worked as assayer for only four years (1697-1701). "E" assayer struck for 13 years (1666-1679) and is another reason why I believe "E" struck this Cob. Again, both of us are correct with the coins origin and time frame which answers VBFD53 with ample detail. The untrained eye would never see what we're looking at, and I appreciate your interest and opinion of my observations.
Trez, Again, there's nothing visible on this coin which would allow us to be absolutely certain in trying to identify the assayer. We could probably go back and forth on it for eternity. Yes, the historical data regarding the new world Spanish mints are constantly changing, but nothing drastic. Most of what we know is good. I grabbed my Sellschopp off the book shelf for reference, but didn't look at any of my other books concerning this coin. Thanks for pointing out the change, I'll have to take as look.
