This just may be the real McCoy...some kind of animal fang tooth. It's been smoothed and has a wonderful warm caramel/beige color and is mounted in rolled gold.
In the Victorian era, during the reign of Britian's Queen Victoria, hunters were in the habit of bringing home trophies, mostly skins and other parts of animals to adorn their "library" or as we now say "man cave". I think they also brought home teeth of animals they killed and had them made into jewelry. I'm not an expert in jewelry of that kind but this does look like a real animal tooth. I'll let the pictures tell you.
The gold is not marked and I have not tested it. I believe the value is in the appearance of the pin, the gold value would be a bonus! There is a simple "C" clasp without a lock, the pin is straight, the hinge works perfectly. There is an initial on the hub end of the pin which looks like a script written letter "B" but I'm not sure.
1 3/4" long .2 oz