These plaques/medallions were sold at the Exposition Universelle of the year 1867.

They are 111 mm or 4.3/8 inches. Produced by the Frenchman M. Latry.

The "real story" is what they are made from:

Animal blood (mainly ox-blood was used) and very fine sawdust, know as wood flour. This blood/wood mixture was pressed in moulds which were then heated, producing a very hard finish which showed fine detail and was very strong. The process was developed by Lepage and Talrich in 1855 and patented under the name BOIS DURCI, later they sold the rights to M. Latry. The objects produced resembled carved ebony, but being mass produced (from basically waste by-products), they were considerably cheaper.

He produced combs, picture frames, plaques, ink-wells, etc using this process. There are some good websites with additional information if anyone is interested, I include just one Bois Durci Information Centre

Okay, now that's something I had no idea of. "Bois durci" is a rather vague term for what it really is!!

Until yesterday I had no idea of them either.

Bois Durci: literally french for ‘hardened wood’. The portrait plaques were popular and in fact some casts were taken from them and bronze medals produced. If you look closely under the bust of Albert you can see a small wing emblem, it is also on the other one but harder to see. It appears on most of the portrait plaques but not all.

Well, I learned something new today...

Fascinating subject, thanks for posting this.

I never heard of "Bois Durci" before today.

It resembles a bronze "reverse proof" (with the shiny portraits and "frosted" fields).