I see a stone, the center stone, a teardrop shaped stone, that is not Turquoise, it is Gem Silica Chrysocolla with Malachite inclusions, the color and variety indicate Inspiration Mine, Globe, Arizona, actually the Live Oak Pit part of the mine......Operated mainly in 1897 to 1920......the date on your piece is not legible but it would help determine if the blue green stones were a later replacement or original.....the stone to the immediate left of the Gem Silica also appears to be Chrysocolla, but this time instead of the Chalcedony variety it looks to be the quartz variety from Mexico found at a much later date......I would at least perform a scratch test to determine if the stone were Turquoise, I guarantee the center stone is not. Also the far left stone is Amazonite, a stone found in Colorado since 1876, something tells me that the stones have been replaced over the years with similar looking stones.....the work is not from some great Jewelry Salon of the time but possibly a local craftsperson, the work is very nice but and it appears to have some mass produced components as well, I think that unless you have some historical documentation for anything other than what is obvious, the value will lie in the wallet of the beholder and the price you would sell it at. It would be super cool to find an old photo with someone wearing it! I for one love it!!! But I am biased towards the Chrysocolla