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 — 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 — that is 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.