@Nikkei_Simmer i have used dogs. You can be lucky and get the gems you want reasonably quickly or not. I have also found rainbow gems and pink diamonds by tunneling. Sometimes I find the gem I want after a sim day or two. Sometimes it takes days and often it never happens. Using the chemistry table is much more predictable. You only have 9 or 10 potions available to be discovered. Sims find them at variable rates due to their propensity to fail. But you will get the potion and while working towards it your sim gains logic skill.