Dominican Amber In-Situ
For some reason, this is VERY hard to get ahold of......
Here are 3 pieces of amber from the La Toca mines which is located just north east of Santiago. Each piece has a number of in-situ amber specimens. The rock is heavy. I consider this perfect material to show individuals how the amber looks as it is mined. All amber pieces in the rock are reasonably easy to see. In fact you can see most of them from the pictures.
I doubt that you can find amber in-situ for sale anywhere else.