Mineraldle
Puzzle #25 was xanthiosite.
Xanthiosite is a nickel arsenate mineral. It was first discovered in Germany in 1858 and named by Gilbert Joseph Adam in 1869.
Read about it on Wikipedia →
What the record says
Puzzle 25 ran on 9 Aug 2026 and the answer was xanthiosite, played with 6 guesses against 4 columns. On the record: Crystal system - monoclinic; Strunz group - phosphates-related; Elements - As, Ni, O; Named after - other.
Beyond the grid the record adds Formula - Ni₃(AsO₄)₂; Mohs hardness - 4; Named after - sulfur, yellow.
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
- phosphates-related
- Elements
- As, Ni, O
- Named after
- other
Also on the record
- Formula
- Ni₃(AsO₄)₂
- Mohs hardness
- 4
- Named after
- sulfur, yellow