I know these are fairly common. These were purchased in Albuquerque (where I live). My in-law was a dealer/trader in Old Town and purchased direct from the artists. Based on the kind of artists that came into the store, and distance to the reservation, I am guessing navajo. But I really don’t know. I believe these to be over 20 years old. She owned and wore them herself before giving them to me about 15 years ago. There is some tarnish. They are stamped “stirling”. Both pieces have artist stamps on the backs of the buckles. The brown belt has an arrowhead shaped outline and what looks to be either a “C” or “G” with a period followed by “MTZ” I think. It’s hard to really see clearly. Brown belt strap is about an inch wide, with 17 alternating pieces of two shapes not including the buckle, and the buckle is differently shaped then the rest of the pieces. The black belt is stamped with initials “KS”, and the strap is also an inch wide and there are 9 pieces all the same size including the buckle. I would just like to know how to go about getting an idea of value on these pieces, and where one might sell such things, either online or locally.