Chladniite is an exceptionally rare phosphate mineral discovered primarily in pallasite meteorites. It typically occurs as tiny, transparent tabular crystals associated with olivine and metallic iron-nickel phases.

Hardness

4.5-5

Mohs

Luster

Vitreous to resinous

Streak

White

Transparency

Transparent

mineralrareFillowite Group family

Chladniite

Hardness: 4.5-5
Luster: Vitreous to resinous
Streak: White
Transparency: Transparent

No image

Is this chladniite?

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 chladniite with a known reference. Chladniite sits at Mohs 4.5-5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to resinous.
4
Match the color range
Compare against the expected color range: colorless.
5
Look at form & habit
Crystal system: trigonal. Typical habit: granular, selvage.

Often confused with

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

mineral

Fillowite

Mohs 4.5

How to tell apart: Luster reads vitreous to resinous on Chladniite and subresinous to greasy on Fillowite.

Often found alongside chladniite

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

All properties

Chemical formula: Na₃CaMg₁₁(PO₄)₉
Mohs hardness: 4.5-5
Density: 3.01 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous to resinous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Granular, selvage
Cleavage: Rhombohedral, probable
Rarity: Rare
Uses: Collector
Host rock: As a single grain in a phosphate-rich inclusion in an iron meteorite (Carleton meteorite); in phosphate-rich portions of an acapulcoite-lodranite meteorite

Where rockhounds find chladniite

Classic worldwide localities

Carleton type IIICD iron and GRA 95209 primitive achrondite meteorites (type locality)

Field-hunting tip

Where it forms: As a single grain in a phosphate-rich inclusion in an iron meteorite (Carleton meteorite); in phosphate-rich portions of an acapulcoite-lodranite meteorite. If you start seeing chlorapatite, olivine, pyroxene in float, you are in the right ground. Typical habit: granular, selvage. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify chladniite?+

Mohs hardness is 4.5-5. Luster: vitreous to resinous. The streak is white. Common colors include colorless.

Where is chladniite found?+

Notable localities include Carleton type IIICD iron and GRA 95209 primitive achrondite meteorites (type locality).

What rocks look like chladniite?+

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

What minerals are found with chladniite?+

Chladniite commonly co-occurs with Chlorapatite, Olivine, Pyroxene, Plagioclase, Schreibersite, Nickel-iron. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does chladniite form in?+

Where it forms: As a single grain in a phosphate-rich inclusion in an iron meteorite (Carleton meteorite); in phosphate-rich portions of an acapulcoite-lodranite meteorite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is chladniite used for?+

Chladniite is used in collector.

Find chladniite on the map

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