Some game mechanics not mentioned

Get and upgrade the Gem Display Case production device as soon as possible, because the materials it produces do not consume any stamina. This game has a mechanic where if you simultaneously possess the highest-grade version of three identical materials, someone will immediately buy them at a high price. Currently, my tests show there's no limit to the number of times this can happen, and it applies to any material. However, since emeralds don't consume stamina, as long as you have space, synthesize them as soon as their cooldown is over. Also, the cooldown time for this Gem Display Case cannot be affected by items that prematurely end the cooldown by counting down, so don't waste them. Lastly, money is the most important thing. Some buildings may not require building materials for upgrades, but they will always require money.