Admontite is a very rare borate mineral typically found in evaporite deposits. It occurs as small, colorless tabular crystals and is known primarily from its type locality in Styria, Austria.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

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Admontite

Admontite is a very rare borate mineral typically found in evaporite deposits. It occurs as small, colorless tabular crystals and is known primarily from its type locality in Styria, Austria.

Hardness: 2-3
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this admontite?

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 admontite with a known reference. Admontite 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: vitreous.
4
Match the color range
Compare against the expected color range: colorless.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: euhedral crystals.

Often confused with

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

Often found alongside admontite

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

All properties

Chemical formula: MgB₆O₁₀·7H₂O
Mohs hardness: 2-3
Density: 1.82 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Monoclinic
Crystal habit: Euhedral crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In a gypsum deposit

Where rockhounds find admontite

Classic worldwide localities

Schildmauer, near Admont, Styria, Austria

Field-hunting tip

Where it forms: In a gypsum deposit. If you start seeing gypsum, anhydrite, hexahydrite in float, you are in the right ground. Typical habit: euhedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify admontite?+

Mohs hardness is 2-3. Luster: vitreous. The streak is white. Common colors include colorless.

Where is admontite found?+

Notable localities include Schildmauer, near Admont, Styria, Austria.

What rocks look like admontite?+

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

What minerals are found with admontite?+

Admontite commonly co-occurs with Gypsum, Anhydrite, Hexahydrite, Löweite, Eugsterite, Pyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does admontite form in?+

Where it forms: In a gypsum deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is admontite used for?+

Admontite is used in collector.

Find admontite on the map

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