Khademite is a rare hydrated aluminum sulfate fluoride mineral that typically forms as a secondary encrustation in oxidized ore deposits. Collectors primarily find it as delicate, fibrous, or powdery coatings that can be difficult to distinguish from other sulfate minerals without analytical testing.
Is this khademite?
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 khademite with a known reference. Khademite sits at Mohs 1-2, 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: colorless, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: efflorescences, encrustations.
Often confused with
Khademite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Alunite is the harder of the two (Mohs 3.5-4 vs. 1-2).
How to tell apart: Streak differs, so Khademite leaves white, Jarosite leaves pale yellow; luster reads vitreous on Khademite and subadamantine to vitreous, resinous on fractures on Jarosite.
Often found alongside khademite
Minerals reported to co-occur with khademite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al(SO₄)F·5H₂O
- Mohs hardness
- 1-2
- Density
- 1.925 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Efflorescences, encrustations
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Rarely formed in the oxidized zone of hydrothermal base-metal deposits
Where rockhounds find khademite
Classic worldwide localities
- Lone Pine mine, Wilcox district, near Silver City, Catron Co., New Mexico, USA
- Saghand, Yazd, Iran
- Rammelsberg mine, near Goslar, Harz Mountains, Germany
- Cetine mine, 20 km southwest of Siena, Tuscany, Italy
- Schoeller mine, Libušin, near Kladno, Czech Republic
Field-hunting tip
Where it forms: Rarely formed in the oxidized zone of hydrothermal base-metal deposits. If you start seeing copiapite, amarantite, parabutlerite in float, you are in the right ground. Typical habit: efflorescences, encrustations. Train your eye for that shape before scanning the outcrop.
Common questions
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Find khademite on the map
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