Featured Gold Wash Sterling Enamel Sash pin ID Help Please

Hi all, I picked up this lovely gold washed sterling and blue enamel sash pin today and need help with an ID if possible. My first thought was maybe Finnish because of the F after Sterling in the mark. I checked 925-1000 for Finnish all other Scandinavian marks and didn't see it. Can someone point me in the right direction please?

I did find this one that looks the same, but the mark is different:
https://www.invaluable.com/auction-...el-sash-buckle-brooch-b-make-225-c-7af44ec959

It measures 2-5/8" x 1-5/8". The mark looks like:
STERLING F
R AB Co (not sure about the A)
4142

The photos I took were quick, I can try to get better ones later if it would help.

Thanks for any help

 

I think the mark was identified in another thread in the last 7-10 days.

 

Thanks Holly, I will try looking back to find it

 

It's R Blackinton - here's the thread:

Need help identifying antique cigarette case | Antiques Board (antiquers.com)

add'l info: R. Blackinton & Co. - Online Encyclopedia of Silver Marks, Hallmarks & Makers' Marks (925-1000.com)

 

OMG! You guys are the best!!!!!!

I can see how the mark is IB with a line shape through it. What confused me is the I was so close to the B it looked like it formed an A.

I wonder what he F after Sterling means.

Thank you so much!!!!!!!!

 

The line through the B is a sword. There is no I.

Unfortunately I have no idea what the F is about.