Though it is a farming sim at heart, Stardew Valley offers much more than just growing crops and raising animals. Players are constantly striving to transform their small farms into profitable ventures, and there are numerous valuable items to farm beyond just vegetables. Among these, gemstones stand out—not only for their beauty and value but also for their utility in crafting and as exceptional gifts.
However, scouring the mines day after day in search of the rarest gemstones can become tedious and time-consuming. This is where the 
Crystalarium becomes an invaluable tool. This remarkable device allows players to take a single gemstone or mineral and replicate it into dozens or even hundreds more. Here's a comprehensive guide on how Stardew Valley players can leverage its capabilities.
Updated January 6, 2025, by Demaris Oxman: The 1.6 update has introduced significant changes to Stardew Valley, including subtle adjustments to high-level items like the Crystalarium. It now functions differently when moved or when changing the stones inside. This guide has been updated to reflect these changes and provide the latest information for players.
Obtaining A Crystalarium
To unlock the Crystalarium crafting recipe, players need to reach Level 9 in their mining skill. The materials required to craft this item are:
- 99
Stone: Easily obtainable by breaking rocks on the farm or in the Mines with a Pickaxe. - 5
Gold Bar: Mine Gold Ore at Level 80 and below in the Mines with a Pickaxe. Use 1 Coal to smelt 5 Gold Ore into a Gold Bar at a Furnace. - 2
Iridium Bar: Iridium can be mined in Skull Cavern or obtained daily from the Statue of Perfection. Follow the smelting process mentioned above to create Iridium Bars. - 1
Battery Pack: Place Lightning Rods outdoors during a thunderstorm. Once struck, they will charge up and produce Battery Packs for players to collect.
Even without the crafting recipe or the rare materials, players can still acquire a Crystalarium through alternative means:
- Community Center Bundle: Complete the 25,000g Bundle in the Vault section of the Community Center to receive a Crystalarium as a reward. Simply donate 25,000g to fulfill this bundle.
- 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, players can place their Crystalarium anywhere, whether indoors or outdoors, on the farm or beyond. The Quarry is a favored location for setting up a crystal farm, utilizing numerous machines simultaneously.
The Crystalarium can replicate any mineral or gemstone placed inside, with the exception of Prismatic Shards. Among the options, 
Quartz has the shortest replication time, though it has a low sell value and is abundant in the mines. Conversely, a 
Diamond takes the longest to produce, at 5 days, but its high value makes it the most profitable choice for the Crystalarium.
To move a Crystalarium, strike it with an ax or pickaxe, which will return it to the player's inventory. If the machine is actively replicating a gem, that gem will drop as well. To change the stone inside the Crystalarium, simply interact with it while holding a new stone. For instance, if it's currently replicating Rubies and you want to switch to Diamonds, interact with the machine while holding a Diamond. The Ruby will be ejected, and the Diamond will be inserted.
By placing a few precious gems into the Crystalarium and waiting a few days, players can significantly boost their profits. Moreover, considering how many NPCs in Pelican Town appreciate Diamonds as gifts, you'll not only increase your wealth but also enhance your relationships throughout the community.
