Grumantite is a rare sodium-silicate mineral found primarily in the hyperalkaline complexes of the Kola Peninsula. It typically forms delicate bladed or fibrous white to colorless crystals, often appearing as radiating sprays within nepheline syenite pegmatites.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Grumantite

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

Is this grumantite?

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 grumantite with a known reference. Grumantite 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. Grumantite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Grumantite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: bladed crystals, radiating aggregates, fibrous.

Often confused with

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

Often found alongside grumantite

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

All properties

Chemical formula: NaHSi₂O₅·H₂O
Mohs hardness: 5
Density: 2.44 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Bladed Crystals, Radiating Aggregates, Fibrous
Cleavage: Perfect On {010}
Rarity: Rare
Uses: Collector
Host rock: Hyperalkaline Igneous Rocks, Specifically Pegmatites
Typical price: $50-300 per specimen depending on size and crystal quality

Where rockhounds find grumantite

Classic worldwide localities

Khibiny Massif, Kola Peninsula, Russia
Lovozero Massif, Kola Peninsula, Russia

Field-hunting tip

Look in hyperalkaline igneous rocks, specifically pegmatites country — that is the host setting where grumantite typically forms. If you start seeing nepheline, microcline, aegirine in float, you are in the right ground. Field specimens usually show a bladed crystals, radiating aggregates, fibrous habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify grumantite?+

Mohs hardness is 5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is grumantite found?+

Notable localities include Khibiny Massif, Kola Peninsula, Russia; Lovozero Massif, Kola Peninsula, Russia.

How much is grumantite worth?+

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

What rocks look like grumantite?+

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

What minerals are found with grumantite?+

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

What kind of rock does grumantite form in?+

Grumantite typically forms in hyperalkaline igneous rocks, specifically pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is grumantite used for?+

Grumantite is used in collector.

Find grumantite on the map

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