One sees a fair number of bone dominoes sets described as "Civil War era" which are not, but these are the real deal, I believe American and think perhaps sailor made, wonderfully irregular and buttery smooth, with ebony backs, great rounded corners and three brass pins positioned more or less on the horizontal. There is one - the 4/3 -- that is a bit smaller than the rest,  a substitute either made or borrowed from another set at some point, but which is very much simpatico with the rest. A special complete (28 piece double six) set.

Sold as found in a box not original to them but into which they fit just fine. Dominoes measure 2 3/4" l x 3/4" w x 3/8" thick. A few small edge chips here and there and a little a little greening to the brass pins, which will come off with a wipe if desired.