Lime

Lime is an industrial element used primarily in the production of Steel. It is not a construction material in practice, despite its description suggesting otherwise: Lime cannot be used to build any buildings. Instead, it serves as a refinement ingredient in the Steel recipe, alongside Iron and Refined Carbon.

Lime is obtained by processing several calcium-rich materials in the Rock Crusher. The main sources are Egg Shell, Pokeshell Molt, and Fossil. Egg Shell converts directly at a 1:1 mass ratio, making it a straightforward early source if Pacu or other critters are producing shells. Pokeshell Molts are also valuable, with regular molts yielding more Lime than small ones, and they are the highest-mass source measured in Lime among the listed crusher inputs. Fossil is a less direct source, producing a small amount of Lime along with Sedimentary Rock.

• Egg Shell: 5 kg Egg Shell = 5 kg Lime
• Small Pokeshell Molt: 1 unit = 5 kg Lime
• Regular Pokeshell Molt: 1 unit = 10 kg Lime
• Fossil: 100 kg Fossil = 5 kg Lime + 95 kg Sedimentary Rock

In general, Pacu eggs are considered a strong source of Egg Shell for Lime production because Pacu reproduce quickly and their eggs have high mass. Shine Bugs also reproduce quickly, but their eggs contain less mass than many other critters, so they are a weaker shell source by comparison. Since Lime is mainly consumed by Steel production, the best long-term strategy is usually to build a stable shell supply rather than rely on Fossil.

The most desirable source of Lime is a care package of 150 kg from the Printing Pod. However, the Printing Pod only begins offering this reward after some Lime has already been produced through normal means, and it is a relatively rare package.

Lime is consumed by the Metal Refinery when making Steel:

• 10 kg Lime + 70 kg Iron + 20 kg Refined Carbon = 100 kg Steel

Because Steel is one of the game’s most important advanced materials, Lime effectively acts as a gating resource for mid- and late-game industrial expansion. Keeping a steady supply of shells or molts ensures that Steel production can continue without interruption.