Mineraldle
Puzzle #21 was thénardite.
Thénardite is an anhydrous sodium sulfate mineral, Na2SO4 which occurs in arid evaporite environments, specifically lakes and playas. It also occurs in dry caves and old mine workings as an efflorescence and as a crusty sublimate deposit around fumaroles. It occurs in volcanic caves on Mount Etna, Italy.
What the record says
Puzzle 21 ran on 5 Aug 2026 and the answer was thénardite, played with 6 guesses against 4 columns. On the record: Crystal system - orthorhombic; Strunz group - sulfates-related; Elements - Na, O, S; Named after - person.
Beyond the grid the record adds Formula - Na₂SO₄; Named after - Louis Jacques Thénard.
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
- orthorhombic
- Strunz group
- sulfates-related
- Elements
- Na, O, S
- Named after
- person
Also on the record
- Formula
- Na₂SO₄
- Named after
- Louis Jacques Thénard