Mapimite is a rare zinc-iron arsenate mineral primarily found in the oxidized zones of the Ojuela Mine in Mexico. It is most recognized for its beautiful, honey-yellow, lath-like or bladed crystals that often form radial sprays or distinct clusters.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrare

Mapimite

Hardness: 3
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this mapimite?

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 mapimite with a known reference. Mapimite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: blue, green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: bladed crystals, radial sprays.

Often confused with

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

How to tell apart: Legrandite is the harder of the two (Mohs 4.5 vs. 3).

Often found alongside mapimite

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

All properties

Chemical formula: Zn₂Fe₃(AsO₄)₃(OH)₄(H₂O)₄·6H₂O
Mohs hardness: 3
Density: 2.95 g/cm³
Colors: Blue Green
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Bladed crystals, radial sprays
Cleavage: On {001} and {010}
Rarity: Rare
Uses: Collector
Host rock: A rare secondary mineral in the oxidized zone of an arsenic-rich hydrothermal polymetallic ore deposit

Where rockhounds find mapimite

Classic worldwide localities

Ojuela mine, Mapimí, Durango, Mexico

Field-hunting tip

Where it forms: A rare secondary mineral in the oxidized zone of an arsenic-rich hydrothermal polymetallic ore deposit. If you start seeing scorodite, adamite, smithsonite in float, you are in the right ground. Typical habit: bladed crystals, radial sprays. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mapimite?+

Mohs hardness is 3. Luster: vitreous. The streak is white. Common colors include blue, green.

Where is mapimite found?+

Notable localities include Ojuela mine, Mapimí, Durango, Mexico.

Is mapimite safe to handle?+

Mapimite contains arsenic and calls for real care. Contains arsenic. Wash hands thoroughly after handling and do not inhale dust or ingest. Store securely.

What rocks look like mapimite?+

Mapimite is most often confused with Adamite, Legrandite, Dickthomssenite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with mapimite?+

Mapimite commonly co-occurs with Scorodite, Adamite, Smithsonite, Limonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mapimite form in?+

Where it forms: A rare secondary mineral in the oxidized zone of an arsenic-rich hydrothermal polymetallic ore deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is mapimite used for?+

Mapimite is used in collector.

Find mapimite on the map

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