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