Georgerobinsonite is a rare lead chromate fluoride mineral characterized by its striking orange-red color and adamantine luster. It typically forms thin, tabular crystals in highly oxidized zones of lead-bearing mineral deposits and is a prized target for advanced micro-mineral collectors.

Hardness

2.5-3

Mohs

Luster

Adamantine

Streak

Pale orange

Transparency

Transparent

mineralrare

Georgerobinsonite

Hardness: 2.5-3
Luster: Adamantine
Streak: Pale orange
Transparency: Transparent

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Is this georgerobinsonite?

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 georgerobinsonite with a known reference. Georgerobinsonite 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: pale orange.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: orange-red.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals.

Often confused with

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

mineral

Crocoite

Mohs 2.5-3

How to tell apart: Streak differs, so Georgerobinsonite leaves pale orange, Crocoite leaves yellow-orange.

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Often found alongside georgerobinsonite

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

All properties

Chemical formula: Pb₄(CrO₄)₂(OH)₂FCl
Mohs hardness: 2.5-3
Density: 3.54 g/cm³
Colors: Orange-red
Streak: Pale orange
Luster: Adamantine
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In vugs in silicified rock in a deeply weathered gold-silver-molybdenum-lead-zinc-vanadium, hydrothermal mineral deposit

Where rockhounds find georgerobinsonite

Classic worldwide localities

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

Field-hunting tip

Where it forms: In vugs in silicified rock in a deeply weathered gold-silver-molybdenum-lead-zinc-vanadium, hydrothermal mineral deposit. If you start seeing caledonite, cerussite, diaboleite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify georgerobinsonite?+

Mohs hardness is 2.5-3. Luster: adamantine. The streak is pale orange. Common colors include orange-red.

Where is georgerobinsonite found?+

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

Is georgerobinsonite safe to handle?+

Georgerobinsonite contains hexavalent chromium and lead and calls for real care. Contains lead and chromium; handle with care, avoid creating dust, and wash hands thoroughly after handling.

What rocks look like georgerobinsonite?+

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

What minerals are found with georgerobinsonite?+

Georgerobinsonite commonly co-occurs with Caledonite, Cerussite, Diaboleite, Cr-bearing leadhillite, Matlockite, Murdochite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does georgerobinsonite form in?+

Where it forms: In vugs in silicified rock in a deeply weathered gold-silver-molybdenum-lead-zinc-vanadium, hydrothermal mineral deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is georgerobinsonite used for?+

Georgerobinsonite is used in collector.

Find georgerobinsonite on the map

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