Tschörtnerite is a rare and complex zeolite mineral known for its striking dodecahedral crystal habit. It is found primarily within the cavities of alkaline volcanic rocks in the Eifel region of Germany, often requiring microscopic examination for positive identification.

Hardness

4.5

Mohs

Luster

Vitreous

Streak

Pale blue

Transparency

Transparent

mineralrareZeolite Group family

Tschörtnerite

Hardness: 4.5
Luster: Vitreous
Streak: Pale blue
Transparency: Transparent

Is this tschörtnerite?

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 tschörtnerite with a known reference. Tschörtnerite sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: pale blue.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: light blue.
5
Look at form & habit
Crystal system: cubic. Typical habit: euhedral crystals.

Often confused with

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

mineral

Chabazite

Mohs 4-5

How to tell apart: Streak differs, so Tschörtnerite leaves pale blue, Chabazite leaves white.

How to tell apart: Streak differs, so Tschörtnerite leaves pale blue, Phillipsite leaves white.

Compare →

Often found alongside tschörtnerite

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

All properties

Chemical formula: Ca₄Cu₃K₆Sr₂Ba₂[Al₂₄Si₂₄O₉₆]·nH₂O
Mohs hardness: 4.5
Density: 2.1 g/cm³
Colors: Light blue
Streak: Pale blue
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Euhedral crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Ca-rich xenolith in leucite tephrite lava

Where rockhounds find tschörtnerite

Classic worldwide localities

Bellberg volcano near Mayen, in the Laacher See volcano area, Eifel, Germany (type locality)

Field-hunting tip

Where it forms: Ca-rich xenolith in leucite tephrite lava. If you start seeing calcite, chabazite, phillipsite in float, you are in the right ground. Typical habit: euhedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tschörtnerite?+

Mohs hardness is 4.5. Luster: vitreous. The streak is pale blue. Common colors include light blue.

Where is tschörtnerite found?+

Notable localities include Bellberg volcano near Mayen, in the Laacher See volcano area, Eifel, Germany (type locality).

Is tschörtnerite safe to handle?+

Tschörtnerite contains copper. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like tschörtnerite?+

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

What minerals are found with tschörtnerite?+

Tschörtnerite commonly co-occurs with Calcite, Chabazite, Phillipsite, Gismondine. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tschörtnerite form in?+

Where it forms: Ca-rich xenolith in leucite tephrite lava. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tschörtnerite used for?+

Tschörtnerite is used in collector.

Find tschörtnerite on the map

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