Gerasimovskite is a rare hydrated niobium-titanium hydroxide mineral found primarily in alkaline igneous environments. It typically occurs as massive, dull brown coatings or earthy crusts and is challenging to identify without advanced chemical testing due to its inconspicuous appearance.

Hardness

Mohs

Luster

Pearly

Streak

Yellowish-white

Transparency

Semitransparent

mineralrare

Gerasimovskite

Hardness: 2
Luster: Pearly
Streak: Yellowish-white
Transparency: Semitransparent

Is this gerasimovskite?

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 gerasimovskite with a known reference. Gerasimovskite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: yellowish-white.
3
Read the luster
Hold the specimen under a strong light. Luster: pearly.
4
Match the color range
Compare against the expected color range: brown, gray, light gray.
5
Look at form & habit
Crystal system: amorphous. Typical habit: metamict, platy.

Often confused with

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

mineral

Pyrochlore

Mohs 5-5.5

How to tell apart: Pyrochlore is the harder of the two (Mohs 5-5.5 vs. 2); streak differs, so Gerasimovskite leaves yellowish-white, Pyrochlore leaves brown; luster reads pearly on Gerasimovskite and vitreous to resinous on Pyrochlore.

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Often found alongside gerasimovskite

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

All properties

Chemical formula: MnTi₃Nb₂O₁₂·9H₂O
Mohs hardness: 2
Density: 2.52-2.58 g/cm³
Colors: Brown Gray Light gray
Streak: Yellowish-white
Luster: Pearly
Transparency: Semitransparent
Crystal system: Amorphous
Crystal habit: Metamict, platy
Cleavage: One direction, perfect, micaceous
Rarity: Rare
Uses: Collector
Host rock: As a secondary mineral formed by the late-stage hydrothermal alteration of Nb–Ti minerals (possibly epistolite) within ussingite-bearing pegmatites, associated with alkaline intrusions

Where rockhounds find gerasimovskite

Classic worldwide localities

Found on Mts. Punkaruaiv, Karnasurt, Nepkhe, and Alluaiv, in the Lovozero massif, Kola Peninsula, Russia
Occurs at Nákâlâq, in the Ilímaussaq intrusion, Greenland

Field-hunting tip

Where it forms: As a secondary mineral formed by the late-stage hydrothermal alteration of Nb–Ti minerals (possibly epistolite) within ussingite-bearing pegmatites, associated with alkaline intrusions. If you start seeing ussingite, epistolite, steenstrupine in float, you are in the right ground. Typical habit: metamict, platy. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gerasimovskite?+

Mohs hardness is 2. Luster: pearly. The streak is yellowish-white. Common colors include brown, gray, light gray.

Where is gerasimovskite found?+

Notable localities include Found on Mts. Punkaruaiv, Karnasurt, Nepkhe, and Alluaiv, in the Lovozero massif, Kola Peninsula, Russia; Occurs at Nákâlâq, in the Ilímaussaq intrusion, Greenland.

Is gerasimovskite safe to handle?+

Gerasimovskite contains trace uranium or thorium. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like gerasimovskite?+

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

What minerals are found with gerasimovskite?+

Gerasimovskite commonly co-occurs with Ussingite, Epistolite, Steenstrupine, Neptunite, Albite, Analcime. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gerasimovskite form in?+

Where it forms: As a secondary mineral formed by the late-stage hydrothermal alteration of Nb–Ti minerals (possibly epistolite) within ussingite-bearing pegmatites, associated with alkaline intrusions. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gerasimovskite used for?+

Gerasimovskite is used in collector.

Find gerasimovskite on the map

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