Tounkite is a rare sulfate-rich member of the sodalite group often found in association with silicate-rich metamorphic rocks. It typically displays a pleasant blue hue and is distinguished by its strong fluorescence under short-wave ultraviolet light.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareSodalite Group family

Tounkite

Hardness: 5.5-6
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this tounkite?

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 tounkite with a known reference. Tounkite sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Tounkite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Tounkite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: blue, white, colorless.
5
Look at form & habit
Crystal system: trigonal. Typical habit: tabular crystals, massive.

Often confused with

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

How to tell apart: Streak differs — Tounkite leaves white, Lazurite leaves light blue.

Often found alongside tounkite

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

All properties

Chemical formula: (Na,Ca)₈(Al₆Si₆O₂₄)(SO₄,Cl,CO₃)₂
Mohs hardness: 5.5-6
Density: 2.44 g/cm³
Colors: Blue White Colorless
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Tabular Crystals, Massive
Cleavage: Poor
Fluorescence: Bright White to Yellow Under SW UV
Rarity: Rare
Uses: Collector
Host rock: Alkaline Igneous Rocks, Contact Metamorphosed Limestone
Typical price: $50-300 per specimen

Where rockhounds find tounkite

Classic worldwide localities

Tunkinskye Mountains, Russia
Little Shavaryn Range, Russia

Field-hunting tip

Look in alkaline igneous rocks, contact metamorphosed limestone country — that is the host setting where tounkite typically forms. If you start seeing calcite, diopside, grossular in float, you are in the right ground. Field specimens usually show a tabular crystals, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tounkite?+

Mohs hardness is 5.5-6. It typically shows a vitreous luster. The streak is white. Common colors include blue, white, colorless.

Where is tounkite found?+

Notable localities include Tunkinskye Mountains, Russia; Little Shavaryn Range, Russia.

How much is tounkite 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 tounkite?+

Tounkite is most often confused with Sodalite, Lazurite, Haüyne. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tounkite?+

Tounkite commonly co-occurs with Calcite, Diopside, Grossular, Nepheline. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tounkite form in?+

Tounkite typically forms in alkaline igneous rocks, contact metamorphosed limestone. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tounkite used for?+

Tounkite is used in collector.

Find tounkite on the map

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