Ok we want to help but this is how it works. We need to know how big it is so take a quarter place it next to it and take another picture. We can't help you if all you say is what is this. What kind of area did you find it in how big is it and pics of the front and back are a must.
Thanks for the new pictures! That's a nice chunk of silver. I still can't find a match but I'll keep looking. Do you think it could have gotten flattened?
I'm not an expert, but I'm under the impression that most Navajo and Hopi jewelry was coin silver. Now that silver coins have dried up they must have to purchase silver, but again, I've never heard of Navajo or Hopi made jewelry having a content mark like 925, which is sterling. I've also been told that the 925 indicates it was made in Mexico, which is their mark for sterling. I guess other countries use 925 also, but the US mark is sterling.