Haigerachite is a rare potassium iron phosphate, typically white. It is a secondary phosphate formed on a mine dump. Associated minerals include quartz, pyrite and gypsum. It was first described from the Silberbrünnle mine dump, central Black Forest, Baden-Württemberg, Germany.
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 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Haigerachite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Haigerachite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white.
- 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: Streak differs, so Haigerachite leaves white, Orpiment leaves yellow; luster reads vitreous on Haigerachite and resinous on Orpiment.
How to tell apart: Streak differs, so Haigerachite leaves white, Smithite leaves orange-red; luster reads vitreous on Haigerachite and adamantine on Smithite.
How to tell apart: Streak differs, so Haigerachite leaves white, Trechmannite leaves yellowish-orange; luster reads vitreous 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
- KFe³⁺₃(H₂PO₄)₆(HPO₄)₂·4H₂O
- Mohs hardness
- 2
- Density
- 2.44 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular to Blocky Crystals, Often as Crusts or Aggregates
- Cleavage
- Good On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Dolomitic Marble Cavities
Where rockhounds find haigerachite
Classic worldwide localities
- Silberbrünnle mine dump, Baden-Württemberg, Germany
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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