Polyphite is a rare member of the eudialyte group typically found in agpaitic alkaline igneous rocks. Collectors look for its distinctive tabular crystals often embedded in syenite pegmatites found primarily in the Kola Peninsula of Russia.

Hardness

Mohs

Luster

Vitreous, resinous on fractures, pearly to adamantine on cleavages

Streak

White

Transparency

Translucent to transparent

mineralrareEudialyte Group family

Polyphite

Hardness: 5
Luster: Vitreous, resinous on fractures, pearly to adamantine on cleavages
Streak: White
Transparency: Translucent to transparent

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Is this polyphite?

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 polyphite with a known reference. Polyphite 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. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous, resinous on fractures, pearly to adamantine on cleavages.
4
Match the color range
Compare against the expected color range: yellow, brown, reddish-brown.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular crystals.

Often confused with

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

Often found alongside polyphite

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

All properties

Chemical formula: Na₆(Na₄Ca₂)₂Na₂Ti₂Na₂Ti₂(Si₂O₇)₂(PO₄)₆O₄F₄
Mohs hardness: 5
Density: 3.07 g/cm³
Colors: Yellow Brown Reddish-brown
Streak: White
Luster: Vitreous, resinous on fractures, pearly to adamantine on cleavages
Transparency: Translucent to transparent
Crystal system: Triclinic
Crystal habit: Tabular crystals
Cleavage: {001}, perfect; {110} and {100}, less perfect
Rarity: Rare
Uses: Collector
Host rock: In ultra-agpaitic pegmatites in a differentiated alkalic massif

Where rockhounds find polyphite

Classic worldwide localities

Mt. Alluaiv, Lovozero massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In ultra-agpaitic pegmatites in a differentiated alkalic massif. If you start seeing nepheline, sodalite, analcime in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify polyphite?+

Mohs hardness is 5. Luster: vitreous, resinous on fractures, pearly to adamantine on cleavages. The streak is white. Common colors include yellow, brown, reddish-brown.

Where is polyphite found?+

Notable localities include Mt. Alluaiv, Lovozero massif, Kola Peninsula, Russia.

What rocks look like polyphite?+

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

What minerals are found with polyphite?+

Polyphite commonly co-occurs with Nepheline, Sodalite, Analcime, Potassic feldspar, Albite, Arfvedsonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does polyphite form in?+

Where it forms: In ultra-agpaitic pegmatites in a differentiated alkalic massif. Working float back to the host body is the standard way to chase a fresh occurrence.

What is polyphite used for?+

Polyphite is used in collector.

Find polyphite on the map

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