NEED help with identifying mark IRV sterling on pendant

[tlsuel]

I am having trouble locating this mark. It is on the back of a necklace pendant. It appears to be american but I am not sure. please help!!





.

[dognose]

Thought this one was worth a bump.

Trev.

[twoworlds]

I am Native and stumped, but more likely a trading Post or old store. Navajo type silverwork on edges. Stamp is new looking. is this piece older. Check Barton Wright's book , Amazon has new edition. I will ask other Natives in Arizona and post if we get it. I am trying to find BY in an animal. Oh my. See, Zuni marry Navajo, names change, hallmarks REALLY can change and pre 1935, many had none or they are rubbed off. Also, Taxco and others are SouthWestern and can fool us. Blessings, TwoWorlds :)