Mineraldle

Puzzle #28 was annabergite.

Annabergite is an arsenate mineral consisting of a hydrous nickel arsenate. It is considered a member of the vivianite group and known for its ability to form crystals in a characteristic apple-green color.

Read about it on Wikipedia →

From Wikipedia (CC BY-SA 4.0)

What the record says

Puzzle 28 ran on 12 Aug 2026 and the answer was annabergite, played with 6 guesses against 4 columns. On the record: Crystal system - monoclinic; Strunz group - phosphates-related; Elements - As, H, Ni, O; Named after - place.

Beyond the grid the record adds Formula - Ni₃(AsO₄)₂·8H₂O; Named after - Annaberg-Buchholz.

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, H, Ni, O
Named after
place

Also on the record

Formula
Ni₃(AsO₄)₂·8H₂O
Named after
Annaberg-Buchholz

Play this puzzle →

Today's puzzle · All past answers