Little Purple Velvet Box Surprise

I've learned over the years that nice things often come in Small Packages and when I saw this closed purple velvet fitted box at a country antique store, I was hoping that it still had it's original content. It did and this beautiful 2 1/4" Lady's Lapel pin was inside. It is marked 14 Karat and has rows of tiny seed pearls along the sides and a central stone that I don't recognize. The Velvet box measures only 3 5/8" by 1 3/8" and 1" thick. It has a MOP button that you push to open the case and was sold by a Sparks Street jeweller and optician operating in the late 1800's and early 1900's in Ottawa, Canada. The stone is light green with mottled white striations....could it be a turquoise? I'd appreciate any ideas on the stone/gem, thanks all, RER (BOB)