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. Tuperssuatsiaite leaves a yellowish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Tuperssuatsiaite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: brown, yellowish-brown, reddish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, acicular, radiating clusters.
Often confused with
Tuperssuatsiaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Tuperssuatsiaite leaves yellowish-brown, Nontronite leaves yellow; luster reads pearly on Tuperssuatsiaite and dull on Nontronite.
How to tell apart: Cronstedtite is the harder of the two (Mohs 3.5 vs. 2); streak differs — Tuperssuatsiaite leaves yellowish-brown, Cronstedtite leaves dark greenish-gray; luster reads pearly on Tuperssuatsiaite and vitreous 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
- NaFe³⁺₃Si₈O₂₀(OH)₄·nH₂O
- Mohs hardness
- 2
- Density
- 2.5 g/cm³
- Streak
- Yellowish-brown
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Acicular, Radiating Clusters
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks
- Typical price
- $20-150 thumbnail
Where rockhounds find tuperssuatsiaite
Classic worldwide localities
- Ilímaussaq complex (Greenland)
- Mont Saint-Hilaire (Canada)
Field-hunting tip
Look in alkaline igneous rocks country — that is the host setting where tuperssuatsiaite typically forms. If you start seeing aegirine, microcline, eudialyte in float, you are in the right ground. Field specimens usually show a fibrous, acicular, radiating clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find tuperssuatsiaite on the map
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