Questions on coral and turquoise ring

It's nothing fancy, I liked the simple-ness and the inlay.
Unfortunately I didn't notice at the time a piece of the coral was missing.

There is no sterling stamp, but a magnet does not pull or stick.

The only stamp on it is DJ.

I'm not sure if it's Native American or from Mexico.

Would it be worth trying to get it repaired, even though I don't have the missing piece?
It should I just wear it till its ratty and scrap it (if it's sterling) when is had enough?

 

Pretty! I hope that others will have some knowledge of this.

 

There is a Dennis James, listed in Barton Wright's Hallmarks of the Southwest, as a Navajo jeweler with this stamp. No further information is given, and while he is also listed in Gregory Schaaf's, American Indian Jewelry I, 1200 Artist Biographies, again there is no additional information.

It looks like the design may be an attempt at a peyote bird. I'm not familiar with the artist, or his work, so that's about all I can tell you.

 

The information given by Taupou led me to a few listings for work signed DJ that also attribute to Dennis James. This one estimates a date of 1970s, but I haven't found any confirmation: http://allardauctions.hibid.com/lot/7251432/navajo-concho-belt---dennis-james

 

Thanks a lot for the information!
Its a very helpful start
I found this squash blossom that looks like his stamp as well
http://www.trocadero.com/stores/loo...ames-Sterling-Squash-Native-American-Necklace