Level your dogs up in hunting and when your sim asks them to hunt they can bring back gems, metals and "Something". Something turns out to be (not always mind you) pieces of something you can put together, much like in world adventures when you found pieces of dive well etc. So far I've got pieces of a "Stone Hydrant", "Mini-Dinosaur skeleton" and "Diamond Dog" don't know what these look like yet, only one piece of each! Also the gems/ metals seems to by high quality - my one dog keeps bringing Vampire eye back, and a meteorite that was worth 9,000 Simoleons!!