Mendeleevite-(Nd) is an extremely rare and complex mineral belonging to the mendeleevite group, first discovered in the alkaline pegmatites of the Kola Peninsula. It is typically found as small, brownish octahedral crystals that are notably radioactive. Due to its unique chemical composition involving cesium and rare earth elements, it is a highly sought-after specimen for advanced mineral collectors.

Hardness

5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareMendeleevite group family

Mendeleevite-(Nd)

Hardness: 5-6
Luster: Vitreous
Streak: White
Transparency: Translucent

No image

Is this mendeleevite-(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 mendeleevite-(nd) with a known reference. Mendeleevite-(Nd) sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Mendeleevite-(Nd) leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Mendeleevite-(Nd) typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: brown, yellow-brown, reddish-brown.
5
Look at form & habit
Crystal system: cubic. Typical habit: octahedral crystals.

Often confused with

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

Often found alongside mendeleevite-(nd)

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

All properties

Chemical formula: (Cs,□)₆(◻,Cs,K)₆(◻,Ca,REE)₆(Ca,REE)₆(Ti,Nb,Si)₄₈O₁₂₈(O,F)₈
Mohs hardness: 5-6
Density: 4.15 g/cm³
Colors: Brown Yellow-brown Reddish-brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Cubic
Crystal habit: Octahedral Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Alkaline Pegmatites
Typical price: $100-500 for small crystals

Where rockhounds find mendeleevite-(nd)

Classic worldwide localities

Kola Peninsula (Russia)

Field-hunting tip

Look in alkaline pegmatites country — that is the host setting where mendeleevite-(nd) typically forms. If you start seeing apatite, nepheline, microcline in float, you are in the right ground. Field specimens usually show a octahedral crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mendeleevite-(nd)?+

Mohs hardness is 5-6. It typically shows a vitreous luster. The streak is white. Common colors include brown, yellow-brown, reddish-brown.

Where is mendeleevite-(nd) found?+

Notable localities include Kola Peninsula (Russia).

How much is mendeleevite-(nd) worth?+

Typical asking prices fall in the range of $100-500 for small crystals. Quality, size, and provenance can move individual specimens well outside that range.

Is mendeleevite-(nd) safe to handle?+

This mineral is radioactive. Mendeleevite-(Nd) is radioactive due to its thorium and rare earth element content; handle with care and store in a lead-lined or secure container to limit radiation exposure. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like mendeleevite-(nd)?+

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

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

Mendeleevite-(Nd) commonly co-occurs with Apatite, Nepheline, Microcline. Spotting any of these in float or country rock is a useful trip signal.

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

Mendeleevite-(Nd) typically forms in alkaline pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is mendeleevite-(nd) used for?+

Mendeleevite-(Nd) is used in collector.

Find mendeleevite-(nd) on the map

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