PMC Gold doesn't like to fuse with fired sterling silver metal clay. The same goes for any other metal that oxidizes. the reason being that the oxidization (tarnish) keeps the two metals from combining. I've even tried to combine them in an oxygen-starved environment, buried in carbon. No luck. At first, the metals seemed to be fused together. But then I started polishing and the gold peeled away from the surface of the other metal. This also happens on occasion with the fine silver metal clays. I say on occasion, because it's been hit or miss for me. Sometimes they fuse and other times they don't.
Another important point to understand is that the more the gold/silver combinations are heated and the hotter they get, the larger the chance that the two metals will alloy together creating a new metal that doesn't look like silver or gold. The gold tends to sink into the silver and gets completely lost.
I have also had artists ask how far a package of the clay go if it is rolled very thin. I haven't tried rolling it out very thin and then measuring it. But, I can say that one package of PMC Gold can make several earrings that are two cards thick and it really goes a long way when inlaid into other metal.
Just adding a little gold to your silver pieces allows you to charge quite a lot more for them. You do the math. Making earrings in silver or sterling silver requires the same amount of labor as making them in gold. But gold commands a higher price. By adding a little bling, gold can help you increase both the variety and the value of your work.
Until next time have fun claying around.