Help with hallmark on pendant

[infoseeker1957]

Picked up at Antique store in northern Arizona. The makers mark seems to be the letters OP or CP. Any help with tribal affiliation or artisan would be appreciated.
Thanks.
http://i44.tinypic.com/2vifc7p.jpg

http://i43.tinypic.com/mhr611.jpg

[InstantCash]

I just searched my Hallmarks of the Southwest for you and was unable to locate that hallmark anywhere in the book. My best guess for that piece is that it would have to be Navajo due to the chunkiness of the piece and the use of the turquoise matrix. This piece is newer I would say prob 1980's.