Kogarkoite is a rare sodium sulfate fluoride mineral found primarily in hyper-alkaline igneous environments. It typically occurs as colorless or white tabular crystals that are highly soluble in water, requiring care in handling and storage to prevent degradation.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Kogarkoite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this kogarkoite?

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 kogarkoite with a known reference. Kogarkoite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kogarkoite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Kogarkoite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, pale yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals, massive, granular.

Often confused with

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

Often found alongside kogarkoite

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

All properties

Chemical formula: Na₃(SO₄)F
Mohs hardness: 3.5
Density: 2.66 g/cm³
Colors: Colorless White Pale Yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Massive, Granular
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Alkaline Igneous Rocks
Typical price: $20-150 for thumbnail specimens

Where rockhounds find kogarkoite

Classic worldwide localities

Lovozero Massif, Kola Peninsula, Russia
Mont Saint-Hilaire, Quebec, Canada

Field-hunting tip

Look in alkaline igneous rocks country — that is the host setting where kogarkoite typically forms. If you start seeing villiaumite, nepheline, aegirine in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kogarkoite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, pale yellow.

Where is kogarkoite found?+

Notable localities include Lovozero Massif, Kola Peninsula, Russia; Mont Saint-Hilaire, Quebec, Canada.

How much is kogarkoite worth?+

Typical asking prices fall in the range of $20-150 for thumbnail specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like kogarkoite?+

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

What minerals are found with kogarkoite?+

Kogarkoite commonly co-occurs with villiaumite, nepheline, aegirine, microcline, sodalite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kogarkoite form in?+

Kogarkoite typically forms in alkaline igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kogarkoite used for?+

Kogarkoite is used in collector.

Find kogarkoite on the map

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