SYNTHESIZING IRON ORE
The recipe says that to create iron ore you need an item and two disassembler scroll. And there's three type of disassembler scroll: weapon, armor, and accessory. You can get it from item shop that show randomly.
After that go to bag interface, click rapid to use synthesis interface. I'll use weapon type for example.
It's easy, isn't it? Now you can get 2000+ stone every hour.
SYNTHESIZING RARE ORE
You can get hand grenade from slot or exploration easily. The hardest things to create rare ore is to find mysterious disassembler scroll at black shop (refresh once an half hour). Find as much as you can until you get three different types. It will takes a lot of time, be patient.
The recipe says that you need to synthesize item + mysterious disassembler scroll + hand grenade. Let's do some experiment then.
Choose armor as an item, and use one of mysterious disassembler scroll. Usually, the type that you'll find a lot are for accessory disassembler, so choose another scroll to test it. If you fail, you'll get a feather. Now you know that scroll is not for armor item, maybe it's for weapon. Then do one more synthesis with weapon. Hope you get the right choice now.
After you know all type of scrolls, arrange them like the picture above. So you can easily remember it. Do this bounty quest can give you 5000+ stone.
We can't tell the difference between weapon and the other scroll now. So you need to test it first.