How Low (On Silver Content Below 70%) Can You Go?

On another thread, the unusual 42% silver content of this Mexican coin was brought up: http://goccf.com/t/456086

But, as many of us are aware, the percent of silver specified in coins' compositions varied all over the map for all kinds of reasons over the centuries.

So this thread is about "silver" or billon coins specified at silver contents lower than 70%.

We'll progress like this:
69% - 60% Today - December 16th
59% - 50% December 17th - December 27
49% - 40% December 28 - January 7
39% - 30% January 8 - January 18
29% - 20% January 29 - February 8
19% - 10% Februry 9 - February 19
9% - 0.5% February 20 - March 2

If for some reason you miss the target week, feel free to post a "catch up" coin whenever you can.

I'm betting we will get at least 30 different compositions, maybe more!

The rules:
a) silver content is rounded to the second significant figure (the "ones" digit until the last week). So, 69.8% (which rounds to 70%) is too high; 59.4% rounds to 59% which is ten days away, and so on.
b) silver must be the main precious metal. So if you have a coin that is specified at 90% gold, 5% silver and 5% other, it doesn't count.
c) the silver content must be knowable (from a mint specification, catalog, etc.)
d) in the first week of each grouping, post examples of coins that you own. After the first week, if you are aware of other coins, feel free to discuss them, and they will be added to the list.

I will maintain a running list organized by decreasing silver content and try to update it at least every week (so, please no data dumps from a search engine )

I will start with this 1/4 thaler of Poland from 1657 that sneaks in under the wire at 69% (11/16 pure, or 0.6875)




Bring on your silver coins with 60-70% silver!