Is there a difference in panning each material and type of block and in which place?

So Bony blocks are the best. But what about the other options?

1. I heard in here that sand and gravel are the same, is that still true 2 years after?

2. What about the different types of stone like shale, chert, andesite, conglomerate, etc? Do any of those have different or unique drop rates?

3. What about the place? If i pan near surface copper rocks will i be more likely to find ore?