Kemmlitzite is a rare phosphate-sulfate mineral that occurs as small, distinct rhombohedral crystals. It is primarily found in kaolinized rocks and is sought after by advanced collectors for its complex chemical composition and scarcity.
Is this kemmlitzite?
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 kemmlitzite with a known reference. Kemmlitzite sits at Mohs 5.5, 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, gray brown, light brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: pseudo rhombohedral.
Often confused with
Kemmlitzite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Kemmlitzite is noticeably harder (Mohs 5.5 vs. 3.5-4.5); streak differs, so Kemmlitzite leaves white, Beudantite leaves grayish yellow to green.
How to tell apart: Kemmlitzite is noticeably harder (Mohs 5.5 vs. 4.5).
How to tell apart: Kemmlitzite is noticeably harder (Mohs 5.5 vs. 3.5-4.5); streak differs, so Kemmlitzite leaves white, Corkite leaves yellow.
Often found alongside kemmlitzite
Minerals reported to co-occur with kemmlitzite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SrAl₃(AsO₄)(SO₄)(OH)₆
- Mohs hardness
- 5.5
- Density
- 3.63 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
- Crystal habit
- Pseudo rhombohedral
- Cleavage
- Poor on {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a kaolinized quartz porphyry, in a heavy-fraction separate of undetermined origin as to primary or secondary formation
Where rockhounds find kemmlitzite
Classic worldwide localities
- Kemmlitz kaolin deposit, near Oschatz, Saxony, Germany
Field-hunting tip
Where it forms: In a kaolinized quartz porphyry, in a heavy-fraction separate of undetermined origin as to primary or secondary formation. If you start seeing kaolinite, zircon, anatase in float, you are in the right ground. Typical habit: pseudo rhombohedral. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kemmlitzite?+
Where is kemmlitzite found?+
Is kemmlitzite safe to handle?+
What rocks look like kemmlitzite?+
What minerals are found with kemmlitzite?+
What kind of rock does kemmlitzite form in?+
What is kemmlitzite used for?+
Find kemmlitzite on the map
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