Imhofite is a rare thallium-arsenic sulfosalt primarily found in the Lengenbach quarry in Switzerland. Collectors prize it for its distinct acicular habit and deep, characteristic dark red coloration. Due to its high toxicity and extreme rarity, it is typically restricted to advanced mineral collections.
Is this imhofite?
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 imhofite with a known reference. Imhofite 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. Imhofite leaves a yellowish-orange streak.
- 3Read the lusterHold the specimen under a strong light. Imhofite typically shows a metallic to submetallic luster.
- 4Match the color rangeCompare against the expected color range: dark red, brownish-red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular to prismatic crystals.
Often confused with
Imhofite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Imhofite leaves yellowish-orange, Realgar leaves orange-red; luster reads metallic to submetallic on Imhofite and resinous on Realgar.
How to tell apart: Streak differs — Imhofite leaves yellowish-orange, Orpiment leaves yellow; luster reads metallic to submetallic on Imhofite and resinous on Orpiment.
How to tell apart: Streak differs — Imhofite leaves yellowish-orange, Smithite leaves orange-red; luster reads metallic to submetallic on Imhofite and adamantine on Smithite.
Often found alongside imhofite
Minerals reported to co-occur with imhofite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Tl₅.6As₁₅S₂₅.3
- Mohs hardness
- 2
- Density
- 4.6 g/cm³
- Colors
- Streak
- Yellowish-orange
- Luster
- Metallic to Submetallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Acicular to Prismatic Crystals
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Dolomitic Marble Cavities
- Typical price
- $200-2000 per specimen
Where rockhounds find imhofite
Classic worldwide localities
- Binntal, Valais, Switzerland
- Allchar, North Macedonia
Field-hunting tip
Look in dolomitic marble cavities country — that is the host setting where imhofite typically forms. If you start seeing sartorite, gratonite, baumhauerite in float, you are in the right ground. Field specimens usually show a acicular to prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find imhofite on the map
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