Haigerachite is an extremely rare thallium sulfosalt discovered in the Binn Valley, Switzerland. It occurs as small, delicate yellow to brownish-yellow crystals and is highly sought after by advanced mineral collectors specializing in rare sulfosalts.
Is this haigerachite?
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 haigerachite with a known reference. Haigerachite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Haigerachite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Haigerachite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular to blocky crystals, often as crusts or aggregates.
Often confused with
Haigerachite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Haigerachite is noticeably harder (Mohs 3.5 vs. 1.5-2).
How to tell apart: Haigerachite is noticeably harder (Mohs 3.5 vs. 1.5-2); streak differs — Haigerachite leaves yellow, Smithite leaves orange-red; luster reads resinous on Haigerachite and adamantine on Smithite.
How to tell apart: Haigerachite is noticeably harder (Mohs 3.5 vs. 1.5-2); streak differs — Haigerachite leaves yellow, Trechmannite leaves yellowish-orange; luster reads resinous on Haigerachite and adamantine on Trechmannite.
Often found alongside haigerachite
Minerals reported to co-occur with haigerachite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Tl₂As₂S₄
- Mohs hardness
- 3.5
- Density
- 3.5-3.6 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular to Blocky Crystals, Often as Crusts or Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Dolomitic Marble Cavities
- Typical price
- $100-1000+ for rare micro specimens
Where rockhounds find haigerachite
Classic worldwide localities
- Lengenbach Quarry, Binn Valley, Switzerland
Field-hunting tip
Look in dolomitic marble cavities country — that is the host setting where haigerachite typically forms. If you start seeing realgar, orpiment, pyrite in float, you are in the right ground. Field specimens usually show a tabular to blocky crystals, often as crusts or aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find haigerachite on the map
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