Early Georgian Rose Cut and Table Cut Diamond Ring

Mid 18th century mixed-cut diamond ring. The center rose cut diamond is flanked by two table cut stones. The stones are set in silver while the remainder of the ring is in 18k gold.  The beautiful reeded back and all original details on the shank are intact and appear to be in original condition.  English in origin, circa 1760. 
Sz 7 1/2. Can be sized.