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, so 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, 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.