Mineraldle
Puzzle #67 was akaganeite.
Akaganeite, also written as the deprecated Akaganéite, is a chloride-containing iron(III) oxide-hydroxide mineral, formed by the weathering of pyrrhotite (Fe1−xS), an iron-deficient sulfide.
What the record says
Puzzle 67 ran on 20 Sep 2026 and the answer was akaganeite, played with 6 guesses against 4 columns. On the record: Crystal system - monoclinic; Strunz group - oxides-hydroxides; Elements - Cl, Fe, H, Ni, O; Named after - place.
Beyond the grid the record adds Formula - (Fe³⁺,Ni²⁺)₈(OH,O)₁₆Cl₁.₂₅·nH₂O; Named after - Akagane mine.
Mineraldle builds its record from Wikidata - CC0 1.0. The description above comes from the same place the game credits on every reveal: English Wikipedia verbatim extract, CC BY-SA 4.0. The puzzle itself is still playable in the archive, and every answer that has been and gone is listed on the past-answers page.
How it scored
- Crystal system
- monoclinic
- Strunz group
- oxides-hydroxides
- Elements
- Cl, Fe, H, Ni, O
- Named after
- place
Also on the record
- Formula
- (Fe³⁺,Ni²⁺)₈(OH,O)₁₆Cl₁.₂₅·nH₂O
- Named after
- Akagane mine