Magnesiocanutite is a rare hydrous manganese arsenate mineral typically occurring as small, pale yellow tabular crystals in arid environments. It is primarily found within the highly specific oxidation zones of the Torrecillas mine in Chile. Due to its extreme rarity and arsenic content, specimens are intended strictly for advanced mineral collections.

Hardness
2.5
Mohs
Luster
Vitreous
Streak
White to very pale pink
Transparency
Transparent

Is this magnesiocanutite?

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 magnesiocanutite with a known reference. Magnesiocanutite 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. Streak: white to very pale pink.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: vitreous.
  • 4
    Match the color range
    Compare against the expected color range: pale brownish pink, rose-pink.
  • 5
    Look at form & habit
    Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

Often found alongside magnesiocanutite

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

All properties

Chemical formula
NaMnMg₂[AsO₄]₂[AsO₂(OH)₂]
Mohs hardness
2.5
Density
3.957 g/cm³
Colors
Pale brownish pinkRose-pink
Streak
White to very pale pink
Luster
Vitreous
Transparency
Transparent
Crystal system
Monoclinic
Crystal habit
Tabular crystals
Cleavage
Perfect on {010} and {101}
Rarity
Rare
Uses
Collector
Host rock
From the oxidation of native arsenic and other As-bearing primary phases, followed by later alteration by saline fluids derived from evaporating meteoric water under hyperarid conditions

Where rockhounds find magnesiocanutite

Classic worldwide localities

  • Torrecillas mine, northern Atacama Desert, Iquique Province, Tarapacá Region, Chile

Field-hunting tip

Where it forms: From the oxidation of native arsenic and other As-bearing primary phases, followed by later alteration by saline fluids derived from evaporating meteoric water under hyperarid conditions. If you start seeing anhydrite, canutite, halite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify magnesiocanutite?+
Mohs hardness is 2.5. Luster: vitreous. The streak is white to very pale pink. Common colors include pale brownish pink, rose-pink.
Where is magnesiocanutite found?+
Notable localities include Torrecillas mine, northern Atacama Desert, Iquique Province, Tarapacá Region, Chile.
Is magnesiocanutite safe to handle?+
Magnesiocanutite contains arsenic and calls for real care. Contains arsenic, which is toxic if ingested, inhaled as dust, or handled without proper hygiene; wash hands thoroughly after handling.
What rocks look like magnesiocanutite?+
Magnesiocanutite is most often confused with Canutite, Allactite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with magnesiocanutite?+
Magnesiocanutite commonly co-occurs with Anhydrite, Canutite, Halite, Lavendulan, Magnesiokoritnigite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does magnesiocanutite form in?+
Where it forms: From the oxidation of native arsenic and other As-bearing primary phases, followed by later alteration by saline fluids derived from evaporating meteoric water under hyperarid conditions. Working float back to the host body is the standard way to chase a fresh occurrence.
What is magnesiocanutite used for?+
Magnesiocanutite is used in collector.

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