| Ussingite | |
|---|---|
|   Ussingite from Shkatulka pegmatite, Umbozero mine (Umbozerskii mine), Alluaiv Mt, Lovozero Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia | |
| General | |
| Category | Phyllosilicate minerals | 
| Formula | Na2AlSi3O8OH | 
| IMA symbol | Usg [1] | 
| Strunz classification | 9.EH.20 | 
| Crystal system | Triclinic | 
| Crystal class | Pinacoidal (1) (same H-M symbol) | 
| Space group | P1 | 
| Identification | |
| Color | pale to medium violet, reddish violet; sometimes barely tinted purple | 
| Fracture | irregular/ uneven | 
| Tenacity | brittle | 
| Mohs scale hardness | 6–7 | 
| Luster | sub-vitreous | 
| Streak | white | 
| Diaphaneity | transparent, translucent | 
| References | [2] [3] | 
Ussingite is a silicate mineral with formula Na2AlSi3O8(OH). [4]
It was named for Niels Viggo Ussing (1864–1911), Copenhagen, Denmark.