Olgite is a very rare phosphate mineral found primarily in the hyperalkaline pegmatites of the Kola Peninsula. It typically occurs as small tabular crystals embedded within nepheline syenite complexes and is highly valued by specialized collectors of Russian minerals.

Hardness

4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareGritsovite Group family

Olgite

Hardness: 4.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this olgite?

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 olgite with a known reference. Olgite sits at Mohs 4.5, 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.
4
Match the color range
Compare against the expected color range: blue, blue green.
5
Look at form & habit
Crystal system: trigonal. Typical habit: microscopic crystals, prismatic.

Often confused with

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

How to tell apart: Olgite is noticeably harder (Mohs 4.5 vs. 2-3); streak differs, so Olgite leaves white, Barytolamprophyllite leaves light brown.

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Often found alongside olgite

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

All properties

Chemical formula: (Ba,Sr)(Na,Sr,REE)₂Na(PO₄)₂
Mohs hardness: 4.5
Density: 3.94 g/cm³
Colors: Blue Blue green
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Microscopic crystals, prismatic
Cleavage: Distinct on {0001}
Rarity: Rare
Uses: Collector
Host rock: In nepheline syenite pegmatite in a differentiated alkalic massif

Where rockhounds find olgite

Classic worldwide localities

Mts. Karnasurt and Alluaiv, Lovozero massif, and in the Vuonnemiok River valley, Khibiny massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In nepheline syenite pegmatite in a differentiated alkalic massif. If you start seeing natrosilite, analcime in float, you are in the right ground. Typical habit: microscopic crystals, prismatic. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify olgite?+

Mohs hardness is 4.5. Luster: vitreous. The streak is white. Common colors include blue, blue green.

Where is olgite found?+

Notable localities include Mts. Karnasurt and Alluaiv, Lovozero massif, and in the Vuonnemiok River valley, Khibiny massif, Kola Peninsula, Russia.

What rocks look like olgite?+

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

What minerals are found with olgite?+

Olgite commonly co-occurs with Natrosilite, Analcime. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does olgite form in?+

Where it forms: In nepheline syenite pegmatite in a differentiated alkalic massif. Working float back to the host body is the standard way to chase a fresh occurrence.

What is olgite used for?+

Olgite is used in collector.

Find olgite on the map

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