Tuzlaite is an extremely rare calcium-sodium borate mineral discovered in the salt deposits of Tuzla, Bosnia and Herzegovina. It typically occurs as small, clear, tabular monoclinic crystals embedded within salt-rich evaporite sequences.

Hardness

2-3

Mohs

Luster

Silky to pearly

Streak

White

Transparency

Semitransparent

mineralrare

Tuzlaite

Hardness: 2-3
Luster: Silky to pearly
Streak: White
Transparency: Semitransparent

No image

Is this tuzlaite?

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 tuzlaite with a known reference. Tuzlaite sits at Mohs 2-3, 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: silky to pearly.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Borax

Mohs 2-2.5

How to tell apart: Luster reads silky to pearly on Tuzlaite and vitreous to resinous, may be earthy on Borax.

How to tell apart: Luster reads silky to pearly on Tuzlaite and vitreous on Gowerite.

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Often found alongside tuzlaite

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

Halite
mineral · Mohs 2-2.5

All properties

Chemical formula: NaCaB₅O₈(OH)₂·3H₂O
Mohs hardness: 2-3
Density: 2.21 g/cm³
Colors: Colorless White
Streak: White
Luster: Silky to pearly
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Tabular crystals
Cleavage: On {001}, perfect
Rarity: Rare
Uses: Collector
Host rock: In a saline evaporite deposit, as veins in dolomitic marl between salt layers

Where rockhounds find tuzlaite

Classic worldwide localities

Tuzla salt mine, Bosnia-Herzegovina

Field-hunting tip

Where it forms: In a saline evaporite deposit, as veins in dolomitic marl between salt layers. If you start seeing halite 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 tuzlaite?+

Mohs hardness is 2-3. Luster: silky to pearly. The streak is white. Common colors include colorless, white.

Where is tuzlaite found?+

Notable localities include Tuzla salt mine, Bosnia-Herzegovina.

What rocks look like tuzlaite?+

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

What minerals are found with tuzlaite?+

Tuzlaite commonly co-occurs with Halite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tuzlaite form in?+

Where it forms: In a saline evaporite deposit, as veins in dolomitic marl between salt layers. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tuzlaite used for?+

Tuzlaite is used in collector.

Find tuzlaite on the map

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