Yingjiangite is a rare secondary uranium phosphate mineral that typically forms as delicate, bright yellow platy crystals or powdery crusts. It is most notable for its intense fluorescence under ultraviolet light and is primarily found in the oxidized zones of uranium deposits. Due to its radioactive nature, it is strictly a collector's mineral that requires careful storage and handling practices.

Hardness

2-3

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineralrare

Yingjiangite

Hardness: 2-3
Luster: Pearly
Streak: Yellow
Transparency: Translucent

Is this yingjiangite?

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 yingjiangite with a known reference. Yingjiangite 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. Yingjiangite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Yingjiangite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, yellow-green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: platy crystals, crusts, radial aggregates.

Often confused with

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

mineral

Autunite

Mohs 2-2.5

How to tell apart: Streak differs — Yingjiangite leaves yellow, Autunite leaves pale yellow.

Often found alongside yingjiangite

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

All properties

Chemical formula: K₂Ca(UO₂)₇(PO₄)₄(OH)₆·17H₂O
Mohs hardness: 2-3
Density: 3.37 g/cm³
Colors: Yellow Yellow-green
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Platy Crystals, Crusts, Radial Aggregates
Cleavage: Perfect Basal
Fluorescence: Bright Yellow-green Under UV
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Uranium-bearing Hydrothermal Deposits
Typical price: $50-300 per specimen depending on size and quality

Where rockhounds find yingjiangite

Classic worldwide localities

Yingjiang County, Yunnan Province, China

Field-hunting tip

Look in oxidized zones of uranium-bearing hydrothermal deposits country — that is the host setting where yingjiangite typically forms. If you start seeing uraninite, pyrite, limonite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify yingjiangite?+

Mohs hardness is 2-3. It typically shows a pearly luster. The streak is yellow. Common colors include yellow, yellow-green.

Where is yingjiangite found?+

Notable localities include Yingjiang County, Yunnan Province, China.

How much is yingjiangite worth?+

Typical asking prices fall in the range of $50-300 per specimen depending on size and quality. Quality, size, and provenance can move individual specimens well outside that range.

Is yingjiangite safe to handle?+

This mineral is radioactive. It contains toxic constituents. Radioactive mineral; handle with care. Store in a shielded container, avoid dust inhalation, and wash hands thoroughly after handling. Contains uranium and may pose health risks if ingested or inhaled. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like yingjiangite?+

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

What minerals are found with yingjiangite?+

Yingjiangite commonly co-occurs with uraninite, pyrite, limonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does yingjiangite form in?+

Yingjiangite typically forms in oxidized zones of uranium-bearing hydrothermal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is yingjiangite used for?+

Yingjiangite is used in collector.

Find yingjiangite on the map

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