Trattnerite is a rare hexagonal mineral within the beryl group, primarily distinguished by its magnesium-rich composition. It typically occurs as small prismatic crystals in pegmatitic environments and is primarily sought after by advanced systematic mineral collectors.

Hardness

6-7

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareBeryl Group family

Trattnerite

Hardness: 6-7
Luster: Vitreous
Streak: White
Transparency: Translucent

No image

Is this trattnerite?

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 trattnerite with a known reference. Trattnerite sits at Mohs 6-7, 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: vitreous.
4
Match the color range
Compare against the expected color range: deep blue, yellowish green.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: prismatic.

Often confused with

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

Often found alongside trattnerite

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

All properties

Chemical formula: Fe₂(Mg₃Si₁₂)O₃₀
Mohs hardness: 6-7
Density: 2.68 g/cm³
Colors: Deep blue Yellowish green
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Hexagonal
Crystal habit: Prismatic
Cleavage: Good on {001}, poor on {100}
Rarity: Rare
Uses: Collector
Host rock: In small cavities within a Si-rich xenolith in nephelinite volcanic rock

Where rockhounds find trattnerite

Classic worldwide localities

Stradner Kogel haüyne–nephelinite quarry, near Bad Gleichenberg, eastern Styria, Austria

Field-hunting tip

Where it forms: In small cavities within a Si-rich xenolith in nephelinite volcanic rock. If you start seeing sanidine, plagioclase, quartz in float, you are in the right ground. Typical habit: prismatic. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify trattnerite?+

Mohs hardness is 6-7. Luster: vitreous. The streak is white. Common colors include deep blue, yellowish green.

Where is trattnerite found?+

Notable localities include Stradner Kogel haüyne–nephelinite quarry, near Bad Gleichenberg, eastern Styria, Austria.

What rocks look like trattnerite?+

Trattnerite is most often confused with Beryl, Indialite, Cordierite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with trattnerite?+

Trattnerite commonly co-occurs with Sanidine, Plagioclase, Quartz, Tridymite, Hematite, Orthopyroxene. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does trattnerite form in?+

Where it forms: In small cavities within a Si-rich xenolith in nephelinite volcanic rock. Working float back to the host body is the standard way to chase a fresh occurrence.

What is trattnerite used for?+

Trattnerite is used in collector.

Find trattnerite on the map

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