Gem Finder[]
The Gem Finder is available from Community Center 1 for 1,000 . He will find gems for you. After researching the 2nd mining perk he can find Blood Crystals, this can be turned off in research tab.
Every Gem (except blood crystals) will upgrade tools in the order above. Upgrading tools is much more valuable than selling them to the NPC market. To collect the gems that he finds, you have to click on him periodically, to see if he has found a rock with a gem inside. If you have the tier 4 mining research perk, you can skip this step, because he will automatically collect what he finds.