Mineraldle
Puzzle #26 was gypsum.
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk. Gypsum also crystallizes as translucent crystals of selenite. It forms as an evaporite mineral and as a hydration product of anhydrite.
Read about it on Wikipedia →
What the record says
Puzzle 26 ran on 10 Aug 2026 and the answer was gypsum, played with 6 guesses against 4 columns. On the record: Crystal system - monoclinic; Strunz group - sulfates-related; Elements - Ca, H, O, S. 1 of the 4 columns is blank in the source (Named after), so nobody could score it either way.
Beyond the grid the record adds Formula - CaSO₄·2H₂O; Mohs hardness - 2.
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
- sulfates-related
- Elements
- Ca, H, O, S
- Named after
- Not recorded
Also on the record
- Formula
- CaSO₄·2H₂O
- Mohs hardness
- 2