Gloomwood: All Gems Locations

The first one is located inside a well in the basement of a house near the entrance to the mines. Just climb down the rope and the gem is yours

You can find this gem near a corpse after you disable the electric gate.

The next one sits at the bottom of a pond alongside 2 coins in this room with cool lighting.

In the final section of the mines near the elevator. This is actually located on the other side of the phonograph room. Neat.

This one is located under the waterfall in the same section with the elevator.

The final (as of yet) small gem is displayed to you in all its glory near a phonograph after exiting the mines. Grab it and prepare yourself for the ultimate challenge…

Yep. Same place as the previous gem, just a bit… higher. Currently, the only way to get it is to stack props like this
I recommend saving after each succesful barrel placement, the tower can get a bit wobbly at times.
IMPORTANT! if you enter a different level, the large gem will disappear from your inventory. So leave it at the lighthouse if you want to keep it.