Intersilite is an extremely rare silicate mineral found in hyper-alkaline igneous rocks. It is typically identified by its delicate, pearly-white tabular crystals often forming radial aggregates within pegmatite pockets.

Hardness

3-4

Mohs

Luster

Vitreous to greasy

Streak

White

Transparency

Transparent

mineralrare

Intersilite

Hardness: 3-4
Luster: Vitreous to greasy
Streak: White
Transparency: Transparent

No image

Is this intersilite?

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 intersilite with a known reference. Intersilite 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. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to greasy.
4
Match the color range
Compare against the expected color range: yellow, pinkish yellow, pink.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: anhedral grains.

Often confused with

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

mineral

Lomonosovite

Mohs 3-4

How to tell apart: Streak differs, so Intersilite leaves white, Lomonosovite leaves light rose-cinnamon.

Often found alongside intersilite

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

All properties

Chemical formula: Na₆Mn(Ti,Nb)Si₁₀(O,OH)₂₈·4H₂O
Mohs hardness: 3-4
Density: 2.42 g/cm³
Colors: YellowPinkish yellowPink
Streak: White
Luster: Vitreous to greasy
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Anhedral grains
Cleavage: Perfect on {100}
Rarity: Rare
Uses: Collector
Host rock: In hyperagpaitic pegmatites

Where rockhounds find intersilite

Classic worldwide localities

Mount Alluaiv in the northwestern part of the Lovozero alkaline massif, Kola Peninsula, Russia (type locality)

Field-hunting tip

Where it forms: In hyperagpaitic pegmatites. If you start seeing aegirine, microcline, nepheline in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify intersilite?+

Mohs hardness is 3-4. Luster: vitreous to greasy. The streak is white. Common colors include yellow, pinkish yellow, pink.

Where is intersilite found?+

Notable localities include Mount Alluaiv in the northwestern part of the Lovozero alkaline massif, Kola Peninsula, Russia (type locality).

What rocks look like intersilite?+

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

What minerals are found with intersilite?+

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

What kind of rock does intersilite form in?+

Where it forms: In hyperagpaitic pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is intersilite used for?+

Intersilite is used in collector.

Find intersilite on the map

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