Koenenite is a rare hydrated magnesium aluminum chloride sulfate mineral primarily found in evaporite deposits. Collectors typically search for its characteristic thin, pearly, platy crystals that occur within salt mine environments, often showing a fragile, foliated appearance.

Hardness

1.5-2

Mohs

Luster

Pearly on cleavage surfaces

Streak

White

Transparency

Transparent to translucent

mineralrare

Koenenite

Hardness: 1.5-2
Luster: Pearly on cleavage surfaces
Streak: White
Transparency: Transparent to translucent

Is this koenenite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch koenenite with a known reference. Koenenite sits at Mohs 1.5-2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: pearly on cleavage surfaces.
4
Match the color range
Compare against the expected color range: colorless, light yellow, dark red.
5
Look at form & habit
Crystal system: trigonal. Typical habit: encrustations.

Often confused with

Koenenite vs. its common look-alikes, and how to tell them apart in the field.

mineral

Brucite

Mohs 2.5

How to tell apart: Luster reads pearly on cleavage surfaces on Koenenite and waxy, pearly on cleavage surfaces on Brucite.

Often found alongside koenenite

Minerals reported to co-occur with koenenite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Na₄Mg₉Al₄Cl₁₂(OH)₂₂
Mohs hardness: 1.5-2
Density: 1.82-2.08 g/cm³
Colors: Colorless Light yellow Dark red
Streak: White
Luster: Pearly on cleavage surfaces
Transparency: Transparent to translucent
Crystal system: Trigonal
Crystal habit: Encrustations
Cleavage: {0001}, perfect
Rarity: Rare
Uses: Collector
Host rock: In marine evaporite deposits

Where rockhounds find koenenite

Classic worldwide localities

Justus I, Glückauf-Sarstedt, Wathlingen, and other mines in the Zechstein potash beds, Lower Saxony, and at Stassfurt, 34 km south of Magdeburg, Saxony-Anhalt, Germany
Pilluana, on the Big Huallaga River, about 25 km south of Tarapoto, Peru
Drill cores from the Prairie Evaporite Formation, Saskatchewan, Canada
Jiangcheng, Yunnan Province, China

Field-hunting tip

Where it forms: In marine evaporite deposits. If you start seeing hematite, carnallite, sylvite in float, you are in the right ground. Typical habit: encrustations. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify koenenite?+

Mohs hardness is 1.5-2. Luster: pearly on cleavage surfaces. The streak is white. Common colors include colorless, light yellow, dark red.

Where is koenenite found?+

Notable localities include Justus I, Glückauf-Sarstedt, Wathlingen, and other mines in the Zechstein potash beds, Lower Saxony, and at Stassfurt, 34 km south of Magdeburg, Saxony-Anhalt, Germany; Pilluana, on the Big Huallaga River, about 25 km south of Tarapoto, Peru; Drill cores from the Prairie Evaporite Formation, Saskatchewan, Canada; Jiangcheng, Yunnan Province, China.

What rocks look like koenenite?+

Koenenite is most often confused with Brucite, Talc. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with koenenite?+

Koenenite commonly co-occurs with Hematite, Carnallite, Sylvite, Halite, Kieserite, Anhydrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does koenenite form in?+

Where it forms: In marine evaporite deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is koenenite used for?+

Koenenite is used in collector.

Find koenenite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.