Belle Epoque Brooch - Berg? Berge?

[Hypersparkle]

Found this beauty, but I'm struggling to figure out the maker on it. The person I bought it from said it was French, but who knows. I haven't tested the metal yet, but it looks platinum to me.





I appreciate any insight you can provide.

[Hypersparkle]

Got a couple better photos this morning:

[Aguest]

:::: Does it say "850" and then a dog-head and then a hallmark I can't identify? :::::: It could be French? ::::