Brinrobertsite is a rare silver-rich clay mineral found primarily in the oxidation zones of ore deposits. It is typically identified through analytical techniques like X-ray diffraction, as it appears as unassuming, dull, massive clay material to the naked eye.

Hardness

1-2

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

mineralrareSmectite Group family

Brinrobertsite

Hardness: 1-2
Luster: Dull
Streak: White
Transparency: Opaque

Is this brinrobertsite?

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 brinrobertsite with a known reference. Brinrobertsite sits at Mohs 1-2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Brinrobertsite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Brinrobertsite typically shows a dull luster.
4
Match the color range
Compare against the expected color range: white, pale yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: fine-grained, massive.

Often confused with

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

How to tell apart: Streak differs, so Brinrobertsite leaves white, Nontronite leaves yellow.

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Often found alongside brinrobertsite

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

All properties

Chemical formula: (Ag,Pb)₀.₃(Si,Al)₄O₁₀(OH)₂·nH₂O
Mohs hardness: 1-2
Density: 2.4-2.6 g/cm³
Colors: White Pale Yellow
Streak: White
Luster: Dull
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Fine-grained, Massive
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Oxidized Ore Deposits
Typical price: $50-200 per specimen

Where rockhounds find brinrobertsite

Classic worldwide localities

Broken Hill (Australia)

Field-hunting tip

Look in oxidized ore deposits country, the host setting where brinrobertsite typically forms. If you start seeing quartz, cerussite, galena in float, you are in the right ground. Field specimens usually show a fine-grained, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify brinrobertsite?+

Mohs hardness is 1-2. It typically shows a dull luster. The streak is white. Common colors include white, pale yellow.

Where is brinrobertsite found?+

Notable localities include Broken Hill (Australia).

How much is brinrobertsite worth?+

Typical asking prices fall in the range of $50-200 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is brinrobertsite safe to handle?+

It contains toxic constituents. Contains silver and lead; wash hands thoroughly after handling and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like brinrobertsite?+

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

What minerals are found with brinrobertsite?+

Brinrobertsite commonly co-occurs with Quartz, Cerussite, Galena, Chlorargyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does brinrobertsite form in?+

Brinrobertsite typically forms in oxidized ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is brinrobertsite used for?+

Brinrobertsite is used in collector.

Find brinrobertsite on the map

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