Carlgieseckeite-(Nd) is an extremely rare sodium neodymium calcium phosphate found primarily in the agpaitic rocks of the Ilímaussaq complex. It typically appears as small, reddish-brown platy crystals associated with complex alkaline pegmatites. Collectors prize it for its unique chemical composition featuring neodymium as the dominant rare earth element.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareTundrite Group family

Carlgieseckeite-(Nd)

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this carlgieseckeite-(nd)?

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 carlgieseckeite-(nd) with a known reference. Carlgieseckeite-(Nd) sits at Mohs 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.
4
Match the color range
Compare against the expected color range: reddish-brown, brown.
5
Look at form & habit
Crystal system: trigonal. Typical habit: platy crystals.

Often confused with

Carlgieseckeite-(Nd) vs. its common look-alikes, and how to tell them apart in the field.

Often found alongside carlgieseckeite-(nd)

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

All properties

Chemical formula: NaNdCa₃(PO₄)₃F
Mohs hardness: 5
Density: 3.91 g/cm³
Colors: Reddish-brown Brown
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Platy crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In small cavities in veins of saccharoidal albite cross-cutting augite syenite

Where rockhounds find carlgieseckeite-(nd)

Classic worldwide localities

Kuannersuit (Kvanefjeld) Plateau, Ilímaussaq alkaline complex, South Greenland

Field-hunting tip

Where it forms: In small cavities in veins of saccharoidal albite cross-cutting augite syenite. If you start seeing analcime, fluorapatite, albite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify carlgieseckeite-(nd)?+

Mohs hardness is 5. Luster: vitreous. The streak is white. Common colors include reddish-brown, brown.

Where is carlgieseckeite-(nd) found?+

Notable localities include Kuannersuit (Kvanefjeld) Plateau, Ilímaussaq alkaline complex, South Greenland.

What rocks look like carlgieseckeite-(nd)?+

Carlgieseckeite-(Nd) is most often confused with Bastnäsite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with carlgieseckeite-(nd)?+

Carlgieseckeite-(Nd) commonly co-occurs with Analcime, Fluorapatite, Albite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does carlgieseckeite-(nd) form in?+

Where it forms: In small cavities in veins of saccharoidal albite cross-cutting augite syenite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is carlgieseckeite-(nd) used for?+

Carlgieseckeite-(Nd) is used in collector.

Find carlgieseckeite-(nd) on the map

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