Gwihabaite is a rare ammonium-potassium nitrate mineral typically found as white, fibrous, or acicular coatings in cave environments. It is formed through the interaction of bat guano with limestone cave walls and is extremely soluble, requiring dry conditions for preservation.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareNitrate Minerals family

Gwihabaite

Hardness: ~2
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this gwihabaite?

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 gwihabaite with a known reference. Gwihabaite sits at Mohs ~2, 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, white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: acicular, efflorescences.

Often confused with

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

How to tell apart: Luster reads vitreous on Gwihabaite and silky on Nitrocalcite.

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Often found alongside gwihabaite

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

All properties

Chemical formula: (NH₄)NO₃
Mohs hardness: ~2
Density: 1.77 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Acicular, efflorescences
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: As crusts and efflorescences formed by bacterial action on bat guano in caves

Where rockhounds find gwihabaite

Classic worldwide localities

Temple of Doom Cave and Wow Gdoom Pothole, Namibia
Hall’s, Torch, and Chaos Caves, Transvaal, South Africa

Field-hunting tip

Where it forms: As crusts and efflorescences formed by bacterial action on bat guano in caves. If you start seeing gypsum, syngenite, boussingaultite in float, you are in the right ground. Typical habit: acicular, efflorescences. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gwihabaite?+

Mohs hardness is ~2. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is gwihabaite found?+

Notable localities include Temple of Doom Cave and Wow Gdoom Pothole, Namibia; Hall’s, Torch, and Chaos Caves, Transvaal, South Africa.

What rocks look like gwihabaite?+

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

What minerals are found with gwihabaite?+

Gwihabaite commonly co-occurs with Gypsum, Syngenite, Boussingaultite, Dittmarite, Weddellite, Glushinskite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gwihabaite form in?+

Where it forms: As crusts and efflorescences formed by bacterial action on bat guano in caves. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gwihabaite used for?+

Gwihabaite is used in collector.

Find gwihabaite on the map

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