Antique 10k/12k French / Love Knot Stick Pin with Tiny Opal

This is a small antique stick pin with a French knot or love knot top. In the center, there is a small opal stone that has not been professionally confirmed. Overall, the piece is in very good shape. The pin is unmarked, but it tested electronically consistently as 10k gold. The top tested closer to 12k. There is some discoloration on the back, and it may be tarnish. Likely made around the late-1800s or early-1900s. Approximate Length: 2 in. Approximate Weight: 0.7 grams ***The white stuff is some stubborn polish I used and couldn't get off the pin.