Ussingite is a rare sodium aluminosilicate mineral known primarily for its distinct violet to lavender coloration. It is most often found in alkaline igneous complexes, occurring as massive veins or granular aggregates that fluoresce strikingly under short-wave UV light.
Is this ussingite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch ussingite with a known reference. Ussingite sits at Mohs 6-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: slightly greasy to vitreous; slightly pearly on cleavage planes.
- 4Match the color rangeCompare against the expected color range: white, light violet red, dark violet red, pink, reddish violet.
- 5Look at form & habitCrystal system: triclinic. Typical habit: massive.
Often confused with
Ussingite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads slightly greasy to vitreous; slightly pearly on cleavage planes on Ussingite and vitreous to greasy on Sodalite.
How to tell apart: Ussingite is noticeably harder (Mohs 6-7 vs. 2-2.5); luster reads slightly greasy to vitreous; slightly pearly on cleavage planes on Ussingite and vitreous on Villiaumite.
How to tell apart: Luster reads slightly greasy to vitreous; slightly pearly on cleavage planes on Ussingite and vitreous to greasy; fibrous aggregates are dull to silky on Serandite.
Often found alongside ussingite
Minerals reported to co-occur with ussingite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂AlSi₃O₈(OH)
- Mohs hardness
- 6-7
- Density
- 2.457-2.49 g/cm³
- Streak
- White
- Luster
- Slightly greasy to vitreous; slightly pearly on cleavage planes
- Transparency
- Transparent to translucent
- Crystal system
- Triclinic
- Crystal habit
- Massive
- Cleavage
- Perfect on {110} and {110}
- Rarity
- Rare
- Uses
- Collector, Mineralogical study
- Host rock
- Syenite pegmatites
Where rockhounds find ussingite
Classic worldwide localities
- A number of places in both the Lovozero and Khibiny massifs, Kola Peninsula, Russia
- Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Where it forms: Syenite pegmatites. If you start seeing sodalite, eudialyte, aegirine in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find ussingite on the map
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