Stats: 2.04ct diamond with .30ct accent stones. GIA cert: M color, VS2 clarity, medium blue fluor, 7.74 x 7.26 x 5mm, platinum, size 3.75. As per the seller, the ring is dated circa 1890 and the mount is Argentine.
Seller: https://www.georgianjewelry.com/ Most highly recommended. Technically, I found it on Etsy - her shop name there is ThreeGracesToo.