Though it is a farming sim at heart, Stardew Valley offers much more than just growing crops and raising animals. Players are always looking to turn their small farm into a thriving business, and while vegetables are a key part of that, there are other valuable items to farm, such as gemstones. These shiny rocks are not only beautiful and valuable, they also play crucial roles in crafting and can serve as excellent gifts.
However, scouring the mines daily for the rarest gemstones can become tedious. This is where the 
Crystalarium becomes a game-changer. With this incredible device, players can take a single gemstone or mineral and multiply it into dozens or even hundreds more. Here's how to make the most of the Crystalarium in Stardew Valley.
Updated January 6, 2025, by Demaris Oxman: The 1.6 update has introduced significant changes to Stardew Valley, including subtle tweaks to high-level items like the Crystalarium. Its functionality regarding movement and changing the stones inside has been modified. This guide has been updated to reflect these changes and provide all the latest information players need to know.
Obtaining A Crystalarium
To unlock the Crystalarium crafting recipe, players need to reach Level 9 in their mining skill. The crafting ingredients include:
- 99
Stone: Easily obtained by breaking rocks around the farm or in the Mines with a Pickaxe. - 5
Gold Bar: Mine Gold Ore at Level 80 and below in the mines, then smelt 5 Gold Ore with 1 Coal into a Gold Bar at a Furnace. - 2
Iridium Bar: Mine Iridium in Skull Cavern or receive it daily from the Statue of Perfection, then smelt it into bars. - 1
Battery Pack: Place lightning rods outside during a thunderstorm to collect Battery Packs when they are struck.
Even without the recipe or the rare materials, players can still obtain a Crystalarium through alternative methods:
- Community Center Bundle: Complete the 25,000g Bundle in the Vault section of the Community Center to receive a Crystalarium.
- Museum: Donate at least 50 minerals (Gemstones or Geode Minerals) to the Museum Collection, and Gunther will reward you with a Crystalarium.
Using The Crystalarium
Once crafted, the Crystalarium can be placed anywhere, whether indoors or outdoors, on or off the farm. The Quarry is a favored location for setting up a crystal farm with multiple machines.
The Crystalarium can duplicate any mineral or gemstone except for Prismatic Shards. 
Quartz has the shortest replication time, but due to its low value and abundance in the mines, it's less profitable. On the other hand, 
Diamonds take the longest to replicate at 5 days, yet their high value makes them the most lucrative choice for the Crystalarium.
To move a Crystalarium, simply hit it with an ax or pickaxe to return it to your inventory. If it's currently replicating a gem, that gem will drop as well. To switch the stone inside a working Crystalarium, interact with it while holding the new stone. For example, if it's replicating Rubies and you want to switch to Diamonds, place a Diamond in the machine, and it will eject the Ruby and start replicating the Diamond.
By inserting a few precious gems and waiting a few days, players can see their profits soar. Plus, with many NPCs in Pelican Town appreciating Diamonds as gifts, you'll become quite popular around town too.
