Schwartzembergite is a rare lead-iodine oxychloride mineral typically found in the oxidized zones of arid mining districts in Chile. It usually forms small, deep red, transparent to translucent rhombohedral crystals that are highly sought after by advanced collectors for their distinct adamantine luster and rarity.

Hardness
2.5
Mohs
Luster
Adamantine
Streak
Straw-yellow
Transparency
Translucent

Is this schwartzembergite?

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 schwartzembergite with a known reference. Schwartzembergite 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. Schwartzembergite leaves a straw-yellow streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Schwartzembergite typically shows a adamantine luster.
  • 4
    Match the color range
    Compare against the expected color range: dark red, reddish brown, brown.
  • 5
    Look at form & habit
    Crystal system: tetragonal. Typical habit: flat pyramidal rounded crystals; earthy to compact masses.

Often confused with

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

Often found alongside schwartzembergite

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

All properties

Chemical formula
H₂Pb₅I³⁺O₆Cl₃
Mohs hardness
2.5
Density
7.5-7.7 g/cm³
Streak
Straw-yellow
Luster
Adamantine
Transparency
Translucent
Crystal system
Tetragonal
Crystal habit
Flat Pyramidal Rounded Crystals; Earthy to Compact Masses
Cleavage
Distinct On {001}
Rarity
Rare
Uses
Collector
Host rock
Oxidized Zones of Lead-rich Hydrothermal Mineral Deposits

Where rockhounds find schwartzembergite

Classic worldwide localities

  • Sierra Gorda, Chile
  • San Rafael, Chile

Field-hunting tip

Look in oxidized zones of lead-rich hydrothermal mineral deposits country, the host setting where schwartzembergite typically forms. If you start seeing paratacamite, atacamite, anglesite in float, you are in the right ground. Field specimens usually show a flat pyramidal rounded crystals; earthy to compact masses habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify schwartzembergite?+
Mohs hardness is 2.5. It typically shows a adamantine luster. The streak is straw-yellow. Common colors include dark red, reddish brown, brown.
Where is schwartzembergite found?+
Notable localities include Sierra Gorda, Chile; San Rafael, Chile.
Is schwartzembergite safe to handle?+
It contains toxic constituents. Contains lead and iodine; handle with care, wash hands after handling, and avoid creating or inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.
What rocks look like schwartzembergite?+
Schwartzembergite is most often confused with Diaboleite, Boleite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with schwartzembergite?+
Schwartzembergite commonly co-occurs with Paratacamite, Atacamite, Anglesite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does schwartzembergite form in?+
Schwartzembergite typically forms in oxidized zones of lead-rich hydrothermal mineral deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is schwartzembergite used for?+
Schwartzembergite is used in collector.

Find schwartzembergite on the map

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