Resins are found in tree sap as mentioned above, but the resins you are talking about are synthetic resins. There are hundreds of kinds, but basically they are dense, easily molded plastics. Both cheap curios and expensive works of art are molded from them, just like glass, so you have to look at more than what your gift is made of. The piece you provided a link to is certainly a cheap tourist piece, not a work of art. But that doesn't mean someone wouldn't like it. That would depend obviously upon the individual to whom you intend to give it