Silver Content Of Classical Greek Coins

It's hard to wrap my brain around all that data, but table 3 was interesting.
I also didn't expect to read the coins often had more titanium than copper.

Hello. Recovering from surgery in 1969 I found an interest in error coins...literally. Walking in a mall, I picked up a penny and noticed by some stroke of fate that only the motto read only "-- -- --- WE TRUST"! The point? I've always, since then, paid attention to anything even coin like. The result is the coins pictured below. I found these in a pair of 800 silver cuff links about 10 years ago. Although the obverse looks like the same King, I'm not certain this is so. For, on the reverse you can see there are distinct differences. Anyone knowledgable care to speculate? I'm thinking they may help me, at least a little bit, purchase a $600.00 digital grand piano I've got my eye on. However, I wouldn't want to under represent or over represent either of them. Each weighs exactly 4.2 grams on a digital scale. Apologies for my camera work. If necessary, I can try again.

It only works well for first-generation coins, struck directly from freshly refined silver - which can only be assumed to be the case for mint-cities that were located in a silver mining region. For mints such as Babylon, with no silver mines nearby, coins would be struck from a mixed source of silver, often second-hand and third hand recycled coins from all over the ancient world tossed into the melting pot together. Which no doubt explains why the "Babylon" coins were all over the graph.