Potential Arts& Crafts Mystery Mark

[suplex]

Hello, First off, thanks to everyone who contributes to this site. This has been a resource for me for years now, and it's great to see how it's grown. I have 3 pieces of estate jewelry that all have the same mark. I think they're arts and crafts era, and are certainly studio pieces. I think it's ATC in a triangle.
https://www.dropbox.com/s/2m5subr32avl9 ... 1.JPG?dl=0
https://www.dropbox.com/s/lm1olab7b01cp ... 0.JPG?dl=0
https://www.dropbox.com/s/97qdh32uw8yi1 ... 2.JPG?dl=0
https://www.dropbox.com/s/nlgmco5k89rwe ... 5.JPG?dl=0

[dognose]

Hi,

You are far more likely to get a response if you embed your images, as many people will not click on links.

Trev.