Antique Diamond and Ruby Pendant

An antique 15k yellow gold ruby and diamond brooch that we've converted to a pendant. This has rose cut diamonds and a Burma ruby in the center. Our best guess is this piece is from the 1880's. This is an English piece based on the hallmarks and in antique jewelry they used a process called "Bloomed gold." Unfortunately, removing the pin stem left a few marks on the back but otherwise it in great condition. It is 1 and 7/8 inches long including the bail.