Mineraldle
Puzzle #11 was weddellite.
Weddellite (CaC2O4·2H2O) is a mineral form of calcium oxalate named for occurrences of millimeter-sized crystals found in bottom sediments of the Weddell Sea, off Antarctica. Occasionally, weddellite partially dehydrates to whewellite, forming excellent pseudomorphs of grainy whewellite after weddellite's short tetragonal dipyramids. It was first described in 1936 but only named in 1942.
Read about it on Wikipedia →
What the record says
Puzzle 11 ran on 26 Jul 2026 and the answer was weddellite, played with 6 guesses against 4 columns. On the record: Crystal system - tetragonal; Strunz group - organic-compounds; Elements - C, Ca, H, O; Named after - other.
Beyond the grid the record adds Formula - Ca(C₂O₄)·2H₂O; Named after - Weddell Sea.
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
- tetragonal
- Strunz group
- organic-compounds
- Elements
- C, Ca, H, O
- Named after
- other
Also on the record
- Formula
- Ca(C₂O₄)·2H₂O
- Named after
- Weddell Sea