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, so 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, so 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, 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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