Tuperssuatsiaite is a rare phyllosilicate mineral that typically forms as delicate, radiating acicular crystals or fibrous mats. It is primarily found in the cavities of alkaline pegmatites, often identified by its distinct brown color and association with minerals like aegirine and eudialyte. Due to its fragile habit, collectors should handle specimens with care to avoid damaging the crystalline clusters.
Is this tuperssuatsiaite?
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 tuperssuatsiaite with a known reference. Tuperssuatsiaite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to nearly metallic, dull in aggregate.
- 4Match the color rangeCompare against the expected color range: reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular, bladed.
Often confused with
Tuperssuatsiaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Tuperssuatsiaite leaves brownish yellow, Nontronite leaves white; luster reads vitreous to nearly metallic, dull in aggregate on Tuperssuatsiaite and waxy, resinous, dull on Nontronite.
How to tell apart: Cronstedtite is the harder of the two (Mohs 3.5 vs. 2); streak differs, so Tuperssuatsiaite leaves brownish yellow, Cronstedtite leaves dark olive-green; luster reads vitreous to nearly metallic, dull in aggregate on Tuperssuatsiaite and brilliant on Cronstedtite.
Often found alongside tuperssuatsiaite
Minerals reported to co-occur with tuperssuatsiaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂(Fe,Mn)₃Si₈O₂₀(OH)₂·4H₂O
- Mohs hardness
- 2
- Density
- 2.465 g/cm³
- Colors
- Streak
- Brownish yellow
- Luster
- Vitreous to nearly metallic, dull in aggregate
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular, bladed
- Cleavage
- Good on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage, low-temperature, hydrothermal mineral in veins cutting nepheline syenite and in sodalite-nepheline syenite pegmatite (Tuperssuatsiait Bay, Greenland); in miarolitic cavities in phonolite (Windhoek, Namibia)
Where rockhounds find tuperssuatsiaite
Classic worldwide localities
- Aris quarry, about 25 km south of Windhoek, Namibia
- Saint-Amable, Quebec, Canada
Field-hunting tip
Where it forms: A late-stage, low-temperature, hydrothermal mineral in veins cutting nepheline syenite and in sodalite-nepheline syenite pegmatite (Tuperssuatsiait Bay, Greenland); in miarolitic cavities in phonolite (Windhoek, Namibia). If you start seeing natrolite, albite, orthoclase in float, you are in the right ground. Typical habit: acicular, bladed. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tuperssuatsiaite?+
Where is tuperssuatsiaite found?+
What rocks look like tuperssuatsiaite?+
What minerals are found with tuperssuatsiaite?+
What kind of rock does tuperssuatsiaite form in?+
What is tuperssuatsiaite used for?+
Find tuperssuatsiaite on the map
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