
1) Iron mineral
Found on
https://www.crosswordclues.com/clue/schwertmannite

Schwertmannite is an iron-oxyhydroxysulfate mineral with an ideal chemical formula of {Iron}8{Oxygen}8({Hydroxide})6({Sulfate})·nH2O or Fe3+16O16(OH,SO4)12-13·10-12H2O. It is an opaque tetragonal mineral typically occurring as brownish yellow encrustations. It has a Mohs hardness of 2.5 - 3.5 and a specific gravity of 3.77 - 3.99. It was first d...
Found on
http://en.wikipedia.org/wiki/Schwertmannite
No exact match found.