Ammoniozippeite is a rare secondary uranium sulfate mineral typically found as yellow-orange crusts or small platy crystals in oxidized uranium-bearing ore deposits. Due to its radioactive nature, it is primarily sought after by advanced mineral collectors who specialize in uranium minerals.

Hardness

2.5

Mohs

Luster

Vitreous

Streak

Pale yellow

Transparency

Transparent

mineralrareZippeite Group family

Ammoniozippeite

Hardness: 2.5
Luster: Vitreous
Streak: Pale yellow
Transparency: Transparent

Is this ammoniozippeite?

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 ammoniozippeite with a known reference. Ammoniozippeite 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: pale yellow.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: yellow, yellowish orange.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: platy crystals, crusts, aggregates.

Often confused with

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

mineral

Zippeite

Mohs ~2

How to tell apart: Streak differs, so Ammoniozippeite leaves pale yellow, Zippeite leaves yellow white.

Compare →

Often found alongside ammoniozippeite

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

All properties

Chemical formula: (NH₄)₂[(UO₂)₂(SO₄)O₂]·H₂O
Mohs hardness: 2.5
Density: 4.427-4.470 g/cm³
Colors: Yellow Yellowish orange
Streak: Pale yellow
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Platy crystals, crusts, aggregates
Cleavage: Perfect on {010} and {001}, good on {100}
Fluorescence: Bright yellow-green under UV
Rarity: Rare
Uses: Collector
Host rock: A secondary mineral on the walls of mines in U-V deposits that replaced wood and other organic material in sandstones and conglomerate (roll-front type U-V deposits)

Where rockhounds find ammoniozippeite

Classic worldwide localities

Utah (USA)
Colorado (USA)
Czech Republic

Field-hunting tip

Where it forms: A secondary mineral on the walls of mines in U-V deposits that replaced wood and other organic material in sandstones and conglomerate (roll-front type U-V deposits). If you start seeing blödite, bobcookite, brochantite in float, you are in the right ground. Typical habit: platy crystals, crusts, aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ammoniozippeite?+

Mohs hardness is 2.5. Luster: vitreous. The streak is pale yellow. Common colors include yellow, yellowish orange.

Where is ammoniozippeite found?+

Notable localities include Utah (USA); Colorado (USA); Czech Republic.

Is ammoniozippeite safe to handle?+

Ammoniozippeite contains uranium or thorium and calls for real care. Radioactive material; store in a shielded container and avoid inhalation or ingestion of dust. Handle with gloves and wash hands thoroughly after contact.

What rocks look like ammoniozippeite?+

Ammoniozippeite is most often confused with Zippeite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ammoniozippeite?+

Ammoniozippeite commonly co-occurs with Blödite, Bobcookite, Brochantite, Chalcanthite, Devilline, Dickite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ammoniozippeite form in?+

What is ammoniozippeite used for?+

Ammoniozippeite is used in collector.

Find ammoniozippeite on the map

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