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. Streak: purple.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: copper 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, so Imhofite leaves purple, Realgar leaves red-orange to red; luster reads metallic on Imhofite and resinous to greasy on Realgar.
How to tell apart: Streak differs, so Imhofite leaves purple, Orpiment leaves pale lemon-yellow; luster reads metallic on Imhofite and resinous, pearly on cleavage surface on Orpiment.
How to tell apart: Streak differs, so Imhofite leaves purple, Smithite leaves vermilion; luster reads metallic 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
- 4.39 g/cm³
- Colors
- Streak
- Purple
- Luster
- Metallic
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular to prismatic crystals
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Of hydrothermal origin
Where rockhounds find imhofite
Classic worldwide localities
- Lengenbach quarry, Binntal, Valais, Switzerland (type locality)
Field-hunting tip
Where it forms: Of hydrothermal origin. If you start seeing realgar, lead sulfantimonides in float, you are in the right ground. Typical habit: acicular to prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify imhofite?+
Where is imhofite found?+
Is imhofite safe to handle?+
What rocks look like imhofite?+
What minerals are found with imhofite?+
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Find imhofite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
