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

Pearly

Streak

White

Transparency

Translucent

mineralrare

Intersilite

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

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. Intersilite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Intersilite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: white, colorless.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals, tabular aggregates.

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 — Intersilite leaves white, Lomonosovite leaves yellowish brown; luster reads pearly on Intersilite and vitreous on Lomonosovite.

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: Na₄MnTiSi₁₀O₂₄(OH)₄·5H₂O
Mohs hardness: 3-4
Density: 2.1-2.2 g/cm³
Colors: White Colorless
Streak: White
Luster: Pearly
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Platy Crystals, Tabular Aggregates
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Alkaline Pegmatites
Typical price: $50-300 per specimen

Where rockhounds find intersilite

Classic worldwide localities

Kola Peninsula, Russia
Mount Saint-Hilaire, Canada

Field-hunting tip

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

Common questions

How do you identify intersilite?+

Mohs hardness is 3-4. It typically shows a pearly luster. The streak is white. Common colors include white, colorless.

Where is intersilite found?+

Notable localities include Kola Peninsula, Russia; Mount Saint-Hilaire, Canada.

How much is intersilite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

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?+

Intersilite typically forms in alkaline 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.