@marciosmg
Are you on Pure Black World Tendency in each of the worlds? I've found that Mercurystones weren't that difficult to drop, I got all that I needed in 10 minutes or so.
Cloudstones were more difficult though, I used a trick that allowed me to get chunks faster, by getting 99 Shards on my pack, I got 8 chunks that way in 15 minutes, while I only got 2 chunks in 1 hour before using that trick.
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
