Kahlenbergite is an exceptionally rare potassium aluminum titanate discovered within carbonate-rich xenoliths in volcanic rocks. It typically occurs as small, light brown to yellow-brown grains and is primarily of interest to advanced mineralogists and systematic collectors focusing on rare volcanic species.
Is this kahlenbergite?
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 kahlenbergite with a known reference. Kahlenbergite sits at Mohs 6-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: light brown, yellow-brown, light orange.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: equant to tabular grains, massive.
Often confused with
Kahlenbergite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kahlenbergite
Minerals reported to co-occur with kahlenbergite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KAl₁₁O₁₇
- Mohs hardness
- 6-7
- Density
- 3.4 g/cm³
- Streak
- Light brown
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Equant to tabular grains, massive
- Cleavage
- Good on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- xenoliths in volcanic rocks
Where rockhounds find kahlenbergite
Classic worldwide localities
- Bellerberg Volcano, Eifel, Germany
Field-hunting tip
Where it forms: xenoliths in volcanic rocks. If you start seeing ettringite, calcite, phillipsite-k in float, you are in the right ground. Typical habit: equant to tabular grains, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kahlenbergite?+
Where is kahlenbergite found?+
What rocks look like kahlenbergite?+
What minerals are found with kahlenbergite?+
What kind of rock does kahlenbergite form in?+
What is kahlenbergite used for?+
Find kahlenbergite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
