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Mottramite is a distinct lead-copper vanadate that typically occurs as vibrant green botryoidal crusts or velvety coatings. It is a common secondary mineral in the oxidation zones of ore deposits, often found in association with its dimorph descloizite.

Hardness
3-3.5
Mohs
Luster
Greasy
Streak
Yellowish green
Transparency
Transparent to nearly opaque

Is this mottramite?

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 mottramite with a known reference. Mottramite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: yellowish green.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: greasy.
  • 4
    Match the color range
    Compare against the expected color range: dark green, brown, brown red, brownish black, green.
  • 5
    Look at form & habit
    Crystal system: orthorhombic. Typical habit: encrustations, plumose, radial.

Often confused with

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

Descloizite mineral
mineral
Descloizite
Mohs 3-3.5

How to tell apart: Streak differs, so Mottramite leaves yellowish green, Descloizite leaves orange to brownish red.

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Conichalcite mineral
mineral
Conichalcite
Mohs 4.5

How to tell apart: Conichalcite is the harder of the two (Mohs 4.5 vs. 3-3.5); streak differs, so Mottramite leaves yellowish green, Conichalcite leaves green; luster reads greasy on Mottramite and vitreous to somewhat greasy on Conichalcite.

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Often found alongside mottramite

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

All properties

Chemical formula
PbCu(VO₄)(OH)
Mohs hardness
3-3.5
Density
5.9-6 g/cm³
Colors
Dark greenBrownBrown redBrownish blackGreen
Streak
Yellowish green
Luster
Greasy
Transparency
Transparent to nearly opaque
Crystal system
Orthorhombic
Crystal habit
Encrustations, plumose, radial
Cleavage
None
Rarity
Common
Uses
Collector
Host rock
A secondary mineral in the oxidized zone of vanadium-bearing base metal deposits

Where rockhounds find mottramite

Classic worldwide localities

  • Mammoth-St. Anthony mine, Tiger, Pinal Co., from Bisbee, Cochise Co., at the Total Wreck mine, Pinal Co., in the Apache mine, near Globe, and from the 79 mine, near Hayden, Gila Co., Arizona, USA
  • Mayflower mine, Socorro Peak district, Socorro Co., New Mexico, USA
  • Whale mine, Goodsprings district, Clark Co., Nevada, USA
  • Mottram St. Andrew, Cheshire, England
  • Mina Grande, Arqueros, Coquimbo, Chile
  • Tsumeb, in the Otavi district, Namibia

Field-hunting tip

Where it forms: A secondary mineral in the oxidized zone of vanadium-bearing base metal deposits. If you start seeing descloizite, duftite, mimetite in float, you are in the right ground. Typical habit: encrustations, plumose, radial. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mottramite?+
Mohs hardness is 3-3.5. Luster: greasy. The streak is yellowish green. Common colors include dark green, brown, brown red, brownish black.
Where is mottramite found?+
Notable localities include Mammoth-St. Anthony mine, Tiger, Pinal Co., from Bisbee, Cochise Co., at the Total Wreck mine, Pinal Co., in the Apache mine, near Globe, and from the 79 mine, near Hayden, Gila Co., Arizona, USA; Mayflower mine, Socorro Peak district, Socorro Co., New Mexico, USA; Whale mine, Goodsprings district, Clark Co., Nevada, USA; Mottram St. Andrew, Cheshire, England; Mina Grande, Arqueros, Coquimbo, Chile.
Is mottramite safe to handle?+
Mottramite contains copper, lead and vanadium. Contains lead and copper; always wash hands thoroughly after handling and avoid creating or inhaling dust. Do not ingest.
What rocks look like mottramite?+
Mottramite is most often confused with Descloizite, Conichalcite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with mottramite?+
Mottramite commonly co-occurs with Descloizite, Duftite, Mimetite, Wulfenite, Cerussite, Azurite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does mottramite form in?+
Where it forms: A secondary mineral in the oxidized zone of vanadium-bearing base metal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is mottramite used for?+
Mottramite is used in collector.

Find mottramite on the map

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