Requiem Shard

I have been looking for gems for days, through forum posts, discord posts, extensively IG, and nobody had certain (or any) gems. For example tourmalines - not even one. Some others weren't found as well. There is a chance all the miners are in a gem-monopoly cabal of sorts and hide them away somewhere discretely, but likely there is a bug or adjusting needed to the gem mining system?

Citrines seem pretty plentiful to me from the starting mines. Didn't manage to get any other gems though.

It also often happens that you get a message "You mined an additional resource" but nothing appears in your backpack.

The system is working as intended. Each gem and rock type material is created from certain areas in the caverns. Each Individual type on these lists can be mined from an area of at least 100x100. So, as you dig through the cavern hallways, if you dig through a section of cave wall that isn't a metal type, it will produce a Heavy stone and also if it is in the correct matching area you can also get a secondary resource of the rock type list or a gem from the gem list. Each type has at least three 100x100 areas where they can be found. The rocks map can overlap with the gems map. This also goes for Iron/Tin/Silver/Gold. There is mostly iron everywhere in the caverns, but they are 12 100x100 areas for Tin Ore, twelve 100x100 areas where silver Ore can be found and 8 areas where Gold Ore can be found.
These are the possible gems These are the possible rock types

Thanks for the explanation, Rex! Makes perfect sense then, miners are simply not exploring enough to find the other resources (yet). I think this only adds to the dynamism of the game so all's good.