Victorian silver and niello horseshoe charm

Today was a great day because I got this beautiful Victorian silver and niello horseshoe charm in my mailbox. (Thank you VanityLove) ;-)
Its a perfect match with my silver and niello watch chain and Victorian horeshoe brooch I already showed you here on cw.
Niello is a black mixture of copper, silver, and lead sulphides, used as an inlay on engraved or etched metal. It can be used for filling in designs cut from metal.
My brooch has gold accents, the charm is a bit simple in design and it has silver accents, but still a great match I would say!
Horseshoe is down so no good luck, but a mourning piece.
I also showed you guys my other niello pieces and some of my equestrian-themed jewelry.
There is a stamp in the back of the charm which I cannot decipher...maybe anyone of you can help me with it?
I hope you like it