Mineraldle
Puzzle #8 was tephroite.
Tephroite is the manganese endmember of the olivine group of nesosilicate minerals with the formula Mn2SiO4. A solid solution series exists between tephroite and its analogues, the group endmembers fayalite and forsterite. Divalent iron or magnesium may readily replace manganese in the olivine crystal structure.
What the record says
Puzzle 8 ran on 23 Jul 2026 and the answer was tephroite, played with 6 guesses against 4 columns. On the record: Crystal system - orthorhombic; Strunz group - silicates; Elements - Mn, O, Si; Named after - other.
Beyond the grid the record adds Formula - Mn²⁺₂SiO₄; Mohs hardness - 6; Named after - ash, color.
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
- silicates
- Elements
- Mn, O, Si
- Named after
- other
Also on the record
- Formula
- Mn²⁺₂SiO₄
- Mohs hardness
- 6
- Named after
- ash, color