Hello,
I agree with 1880's, right around 1885 (give or take a couple of years either way). That small collar was very popular then. It is more of a jacket than a coat. The silhouette is similar to a mid 1880s walking jacket, but the silk is more formal. I do think it had more parts to it, as the front seems rather plain. It is almost like a mantle, but the sleeves are too form fitting to be called that.
Lovely.
B