Tatarskite is an exceptionally rare hydrous calcium magnesium sulfate-carbonate-chloride mineral. It typically occurs as small, colorless to white tabular crystals within evaporite sequences and is primarily prized by advanced mineral collectors for its unique chemical composition.

Hardness

2.5

Mohs

Luster

Vitreous, pearly on cleavages

Streak

White

Transparency

Transparent

mineralrare

Tatarskite

Hardness: 2.5
Luster: Vitreous, pearly on cleavages
Streak: White
Transparency: Transparent

No image

Is this tatarskite?

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 tatarskite with a known reference. Tatarskite sits at Mohs 2.5, 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, pearly on cleavages.
4
Match the color range
Compare against the expected color range: colorless, light yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: crystalline.

Often confused with

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

mineral

Gypsum

Mohs 1.5-2

How to tell apart: Luster reads vitreous, pearly on cleavages on Tatarskite and subvitreous, pearly on {010} cleavages, silky if fibrous on Gypsum.

Often found alongside tatarskite

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

All properties

Chemical formula: Ca₆Mg₂(SO₄)₂(CO₃)₂(OH)₄Cl₄·7H₂O
Mohs hardness: 2.5
Density: 2.341 g/cm³
Colors: Colorless Light yellow
Streak: White
Luster: Vitreous, pearly on cleavages
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Crystalline
Cleavage: Two sets of distinct pinacoidal cleavages
Rarity: Rare
Uses: Collector
Host rock: A rare secondary mineral found in drill core in a marine salt deposit

Where rockhounds find tatarskite

Classic worldwide localities

Chelkar salt dome, Ak-saı̆ Valley, Uralsk district, Kazakhstan

Field-hunting tip

Where it forms: A rare secondary mineral found in drill core in a marine salt deposit. If you start seeing anhydrite, halite, bischofite in float, you are in the right ground. Typical habit: crystalline. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tatarskite?+

Mohs hardness is 2.5. Luster: vitreous, pearly on cleavages. The streak is white. Common colors include colorless, light yellow.

Where is tatarskite found?+

Notable localities include Chelkar salt dome, Ak-saı̆ Valley, Uralsk district, Kazakhstan.

What rocks look like tatarskite?+

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

What minerals are found with tatarskite?+

Tatarskite commonly co-occurs with Anhydrite, Halite, Bischofite, Magnesite, Hilgardite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tatarskite form in?+

Where it forms: A rare secondary mineral found in drill core in a marine salt deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tatarskite used for?+

Tatarskite is used in collector.

Find tatarskite on the map

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