Mineraldle
Puzzle #58 was whewellite.
Whewellite is a mineral, hydrated calcium oxalate, formula Ca C2O4·H2O. Because of its organic content it is thought to have an indirect biological origin; this hypothesis is supported by its presence in coal and sedimentary nodules. However, it has also been found in hydrothermal deposits where a biological source appears improbable. For this reason, it may be classed as a true mineral.
Read about it on Wikipedia →
What the record says
Puzzle 58 ran on 11 Sep 2026 and the answer was whewellite, played with 6 guesses against 4 columns. On the record: Crystal system - monoclinic; Strunz group - organic-compounds; Elements - C, Ca, H, O; Named after - person.
Beyond the grid the record adds Formula - Ca(C₂O₄)·H₂O; Named after - William Whewell.
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
- organic-compounds
- Elements
- C, Ca, H, O
- Named after
- person
Also on the record
- Formula
- Ca(C₂O₄)·H₂O
- Named after
- William Whewell