Diaboleite is a striking rare lead-copper halide mineral typically found as deep blue square, tabular crystals. It is best known by collectors for its association with lead-ore oxidation zones, particularly in the historic mines of the Mendip Hills in England.

Hardness
2.5
Mohs
Luster
Vitreous
Streak
Pale Blue
Transparency
Translucent

Is this diaboleite?

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 diaboleite with a known reference. Diaboleite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Diaboleite leaves a pale blue streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Diaboleite typically shows a vitreous luster.
  • 4
    Match the color range
    Compare against the expected color range: deep blue, bright blue.
  • 5
    Look at form & habit
    Crystal system: tetragonal. Typical habit: tabular crystals, thick square plates, crusts.

Often confused with

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

Often found alongside diaboleite

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

All properties

Chemical formula
Pb₂CuCl₂(OH)₄
Mohs hardness
2.5
Density
5.4-5.5 g/cm³
Streak
Pale Blue
Luster
Vitreous
Transparency
Translucent
Crystal system
Tetragonal
Crystal habit
Tabular Crystals, Thick Square Plates, Crusts
Cleavage
Perfect On {001}
Rarity
Rare
Uses
Collector
Host rock
Oxidized Zones of Lead-copper Deposits
Typical price
$50-500 depending on crystal size and matrix quality

Where rockhounds find diaboleite

Classic worldwide localities

  • Mendip Hills, England
  • Mammoth-St. Anthony Mine, Arizona
  • Laurion, Greece
  • Sierra Gorda, Chile

Field-hunting tip

Look in oxidized zones of lead-copper deposits country — that is the host setting where diaboleite typically forms. If you start seeing cerussite, hydrocerussite, matlockite in float, you are in the right ground. Field specimens usually show a tabular crystals, thick square plates, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify diaboleite?+
Mohs hardness is 2.5. It typically shows a vitreous luster. The streak is pale blue. Common colors include deep blue, bright blue.
Where is diaboleite found?+
Notable localities include Mendip Hills, England; Mammoth-St. Anthony Mine, Arizona; Laurion, Greece; Sierra Gorda, Chile.
How much is diaboleite worth?+
Typical asking prices fall in the range of $50-500 depending on crystal size and matrix quality. Quality, size, and provenance can move individual specimens well outside that range.
Is diaboleite safe to handle?+
It contains toxic constituents. Contains lead and copper. Wash hands thoroughly after handling and avoid inhaling dust or powder. Handle with care, avoid grinding or breathing dust, and store separately.
What rocks look like diaboleite?+
Diaboleite is most often confused with Boleite, Cumengeite, Pseudoboleite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with diaboleite?+
Diaboleite commonly co-occurs with cerussite, hydrocerussite, matlockite, phosgenite, malachite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does diaboleite form in?+
Diaboleite typically forms in oxidized zones of lead-copper deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is diaboleite used for?+
Diaboleite is used in collector.

Find diaboleite on the map

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