Hello all. Sorry it took me a while to respond, it's been a very busy time.
I'm excited to see even more Isabel's posted!
In terms of weight: 20 Reales of the decree of 1848, 1848-1863 26.29g and 2 Escudos of the decree of 1864, 1865-1868 25.96g
It should be noted that there is a variation in the weight of these coins when they leave the mint. My research indicates that is about 0.15g.
Also, although my studies still need more samples, I've found that for these particular coins the wear on an authentic coin in EF condition accounts for as much as another 1% loss. Also, coins that are cleaned lose approximately 0.4% to 0.7% of their weight to the cleaning. My current best estimate of a cleaned EF coin is that it could have up to 1.4% loss from design weight + manufacturing tolerance. At VF (estimated 2.2%) and below the weight loss is more significant, reaching about 3% loss at F/VG.
So it is possible for a 20 reales in EF that was cleaned to weight as little as 26.29 - 0.15 - (26.29*0.014) = 25.77g And, of course, a VF/F coin would weight a bit less.
Certainly, if a coin is off by 5% or more it's highly suspect and would warrant other tests to confirm.
Plonker, I hope your interpretation of my previous comments did not lead you to believe your coin is counterfeit. For my part, I don't know yet. I was simply suggesting another point of information to verify.
That said, I was remiss in not asking the diameter of the coin. For these 20 reales 37.0 to 37.2mm is what I would generally expect. Remember to measure at several points and take the largest measurement.
Also, as part of my ongoing studies I would be very grateful for any thickness measurements you folks might be willing to provide. Ideally, I would like measurements at the rim at 3 or 4 points roughly equidistant from each other around the perimeter. Please identify the year/mint associated with each set of measurements. Many thanks!
