I hacked gemstones in 1.2.42. Using Bluestacks and GG, with the game offline. I did a fuzzy til I found the gemstones hex. Then set both lines (there were 2 #s, and each gemstone is like a long #. Example: x,*****,*****). I set each of the 2 values to the max negative allowed in the range (it says in GG while editing it what the range is). I froze them. Then checked inventory. The gem value was at 92 mil. I was able to do this on all types of brilliant gemstones to get 92 mil each.
Basically, here's how i edited gemstones:
1. search for fuzzy dword
2. socket 1 gemstone into gear, search for change value. repeat until few options left, play game a bit, etc, get values down to a few.
3. 2 memory values should be close in range, with big nubmers. The encryption is reversed. Edit them both to max negative and freeze. This will give 92mil gemstones.
5. I then turned my internet back on, and made sure the game saved. I closed it, then logged onto my android before the game could freeze or revert back (which can happen).
You can see I used it to get gold too, just sold a fat stack of gemtones for 600+ mil