Direct answer

The Philosopher’s Stone is produced at the top of the late-game chain and awards “The Legendary Stone — Produce a Philosopher’s Stone” (2.5% of players). It is the wiki’s golden-record item for recursive upstream graphs: several of its ingredients are themselves products of deep chains.

CategoryRelic / legendary good
Evidence“The Legendary Stone” — 2.5%
Chain depthRecursive — inputs need their own chains
RelatedCauldron, essences, planet items
1.0 statusPresent; exact path PENDING

The recursive chain

The stone’s signature: producing it requires items that are late-game products themselves, so you plan a multi-stage upstream graph — not a single recipe. This is why calculator and planner tools are planned after the wiki data matures (see About & roadmap).

End-game achievements cluster around the stone: Crown (1.9%), Sol / Luna / Mercury / Venus (0.6–5.8%), and essence conversions like Oblivion Essence via the Cauldron. Community discussion treats these as the same late-game loop.

When to start planning

  1. Stabilize Saturn/Mars-tier production (achievements: 13.4% / 9.2%).
  2. Build the essence conversion loop in the Cauldron.
  3. Chain the planet-tier items into the stone’s ingredients.
  4. Produce the stone — and, if you can, within 50 days for “Born with the Talent”.
Evidence boundary

Item existence and achievement: OFFICIAL. The concrete recipe branch is PENDING until the 1.0 chain is verified end to end.

Independent fan reference for Alchemy Factory. Game data refers to the current official 1.0 build (Steam, PC). Field-level evidence is flagged on each page with OFFICIAL / OBSERVED / COMMUNITY badges; amounts shown without a badge come from the official 1.0 patch notes or store descriptions.