Delindeite is an extremely rare titanosilicate mineral found primarily in alkaline pegmatites of the Kola Peninsula. It typically occurs as small, delicate, pale pinkish gray platy crystals or radial clusters associated with other rare alkaline minerals.

Hardness

3-4

Mohs

Luster

Resinous to Pearly

Streak

White

Transparency

Translucent

mineralrareLabuntsovite Group family

Delindeite

Hardness: 3-4
Luster: Resinous to Pearly
Streak: White
Transparency: Translucent

Is this delindeite?

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 delindeite with a known reference. Delindeite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Delindeite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Delindeite typically shows a resinous to pearly luster.
4
Match the color range
Compare against the expected color range: pale pinkish gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals, radial aggregates.

Often confused with

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

mineral

Nenadkevichite

Mohs 5

How to tell apart: Nenadkevichite is the harder of the two (Mohs 5 vs. 3-4); luster reads resinous to pearly on Delindeite and vitreous on Nenadkevichite.

Compare →

Often found alongside delindeite

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

All properties

Chemical formula: (Na,K,Ba)₂(Ti,Fe,Mg)₂(Si₂O₇)₂(O,OH)₂·nH₂O
Mohs hardness: 3-4
Density: 3.32 g/cm³
Colors: Pale Pinkish Gray
Streak: White
Luster: Resinous to Pearly
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Platy Crystals, Radial Aggregates
Cleavage: {001}, Good
Rarity: Rare
Uses: Collector
Host rock: Alkaline Pegmatites

Where rockhounds find delindeite

Classic worldwide localities

Diamond Jo quarry, Hot Springs County, Arkansas, USA

Field-hunting tip

Look in alkaline pegmatites country, the host setting where delindeite typically forms. If you start seeing microcline, aegirine, nepheline in float, you are in the right ground. Field specimens usually show a platy crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify delindeite?+

Mohs hardness is 3-4. It typically shows a resinous to pearly luster. The streak is white. Common colors include pale pinkish gray.

Where is delindeite found?+

Notable localities include Diamond Jo quarry, Hot Springs County, Arkansas, USA.

What rocks look like delindeite?+

Delindeite is most often confused with Nenadkevichite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with delindeite?+

Delindeite commonly co-occurs with Microcline, Aegirine, Nepheline, Eudialyte. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does delindeite form in?+

Delindeite typically forms in alkaline pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is delindeite used for?+

Delindeite is used in collector.

Find delindeite on the map

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