Kaliborite is a rare hydrated potassium-magnesium borate mineral found in evaporite deposits. It typically occurs as white, bladed crystals or granular masses and is primarily sought after by advanced mineral collectors specializing in borates.

Hardness

4-4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareBorate family

Kaliborite

Hardness: 4-4.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this kaliborite?

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 kaliborite with a known reference. Kaliborite sits at Mohs 4-4.5, 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.
4
Match the color range
Compare against the expected color range: white, colorless, gray white, reddish brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: bladed crystals, granular masses.

Often confused with

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

mineral

Borax

Mohs 2-2.5

How to tell apart: Kaliborite is noticeably harder (Mohs 4-4.5 vs. 2-2.5).

Often found alongside kaliborite

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

All properties

Chemical formula: KHMg₂B₁₂O₁₆(OH)₁₀·4H₂O
Mohs hardness: 4-4.5
Density: 2.128 g/cm³
Colors: White Colorless Gray white Reddish brown
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Bladed crystals, granular masses
Cleavage: On {001}, {101}, perfect; on {100}, good
Rarity: Rare
Uses: Collector
Host rock: An uncommon component in marine potash deposits; rarely in efflorescences

Where rockhounds find kaliborite

Classic worldwide localities

Eagle Borax Spring, Furnace Creek district, Death Valley, Inyo Co., California, USA
Saxony-Anhalt, from Schmidtmannshall, near Aschersleben, Germany
Neustassfurt and Leopoldshall, in Stassfurt, 34 km south of Magdeburg, Germany
Sallent-Balsareny, Barcelona Province, Spain
Monte Sambuco, Calascibetta, Sicily, Italy
Inder borate deposit, Kazakhstan

Field-hunting tip

Where it forms: An uncommon component in marine potash deposits; rarely in efflorescences. If you start seeing boracite, pinnoite, kainite in float, you are in the right ground. Typical habit: bladed crystals, granular masses. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kaliborite?+

Mohs hardness is 4-4.5. Luster: vitreous. The streak is white. Common colors include white, colorless, gray white, reddish brown.

Where is kaliborite found?+

Notable localities include Eagle Borax Spring, Furnace Creek district, Death Valley, Inyo Co., California, USA; Saxony-Anhalt, from Schmidtmannshall, near Aschersleben, Germany; Neustassfurt and Leopoldshall, in Stassfurt, 34 km south of Magdeburg, Germany; Sallent-Balsareny, Barcelona Province, Spain; Monte Sambuco, Calascibetta, Sicily, Italy.

What rocks look like kaliborite?+

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

What minerals are found with kaliborite?+

Kaliborite commonly co-occurs with Boracite, Pinnoite, Kainite, Anhydrite, Halite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kaliborite form in?+

Where it forms: An uncommon component in marine potash deposits; rarely in efflorescences. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kaliborite used for?+

Kaliborite is used in collector.

Find kaliborite on the map

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