Pinalite is a very rare lead tungsten oxychloride primarily known from the Mammoth-St. Anthony Mine in Tiger, Arizona. It typically forms small, vibrant yellow to orange-yellow tabular crystals or crystalline crusts associated with other secondary lead minerals.

Hardness

2.5-3

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Pinalite

Hardness: 2.5-3
Luster: Adamantine
Streak: White
Transparency: Transparent

No image

Is this pinalite?

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 pinalite with a known reference. Pinalite sits at Mohs 2.5-3, 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: adamantine.
4
Match the color range
Compare against the expected color range: yellow, orangish, golden yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: acicular, bladed, microscopic crystals.

Often confused with

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

mineral

Wulfenite

Mohs 2.75-3

How to tell apart: Luster reads adamantine on Pinalite and resinous, subadamantine to adamantine on Wulfenite.

Often found alongside pinalite

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

All properties

Chemical formula: Pb₃(WO₄)OCl₂
Mohs hardness: 2.5-3
Density: 7.78 g/cm³
Colors: YellowOrangishGolden yellow
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Acicular, bladed, microscopic crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: A late-stage secondary mineral in the oxidized zone of a base-metal deposit

Where rockhounds find pinalite

Classic worldwide localities

Mammoth-St. Anthony mine, Tiger, Pinal Co., Arizona, USA

Field-hunting tip

Where it forms: A late-stage secondary mineral in the oxidized zone of a base-metal deposit. If you start seeing chromian leadhillite, cerussite, matlockite in float, you are in the right ground. Typical habit: acicular, bladed, microscopic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify pinalite?+

Mohs hardness is 2.5-3. Luster: adamantine. The streak is white. Common colors include yellow, orangish, golden yellow.

Where is pinalite found?+

Notable localities include Mammoth-St. Anthony mine, Tiger, Pinal Co., Arizona, USA.

Is pinalite safe to handle?+

Pinalite contains lead. Contains lead, which is toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust when breaking specimens.

What rocks look like pinalite?+

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

What minerals are found with pinalite?+

Pinalite commonly co-occurs with Chromian leadhillite, Cerussite, Matlockite, Diaboleite, Caledonite, Connellite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does pinalite form in?+

Where it forms: A late-stage secondary mineral in the oxidized zone of a base-metal deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is pinalite used for?+

Pinalite is used in collector.

Find pinalite on the map

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