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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: pseudo hexagonal, scaly, spherical.
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 pale lemon-yellow; luster reads vitreous on Haigerachite and resinous, pearly on cleavage surface on Orpiment.
How to tell apart: Streak differs, so Haigerachite leaves white, Smithite leaves vermilion; luster reads vitreous on Haigerachite and adamantine on Smithite.
How to tell apart: Streak differs, so Haigerachite leaves white, Trechmannite leaves scarlet-vermilion; 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 to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Pseudo hexagonal, scaly, spherical
- Cleavage
- Good on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary phosphate formed on a mine dump
Where rockhounds find haigerachite
Classic worldwide localities
- Silberbrünnle mine dump, upper Haigerachtal, near Gengenbach, central Black Forest, Baden-Württemberg, Germany
Field-hunting tip
Where it forms: A secondary phosphate formed on a mine dump. If you start seeing quartz, pyrite, gypsum in float, you are in the right ground. Typical habit: pseudo hexagonal, scaly, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
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Find haigerachite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
