Minguzzite is an extremely rare iron oxalate mineral typically found in guano-rich environments or specific fumarolic conditions. It usually appears as small, emerald-green tabular crystals or fine crusts that are highly sensitive to moisture and light.
Is this minguzzite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch minguzzite with a known reference. Minguzzite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: green, yellow green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular.
Often confused with
Minguzzite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside minguzzite
Minerals reported to co-occur with minguzzite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₃Fe(C₂O₄)₃·3H₂O
- Mohs hardness
- 2-3
- Density
- 2.080 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular
- Cleavage
- Perfect on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Rare, in an oxidized gossan formed in a calcareous dolomite
Where rockhounds find minguzzite
Classic worldwide localities
- Capo Calamita, Elba, Italy
Field-hunting tip
Where it forms: Rare, in an oxidized gossan formed in a calcareous dolomite. If you start seeing humboldtine, limonite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify minguzzite?+
Where is minguzzite found?+
What rocks look like minguzzite?+
What minerals are found with minguzzite?+
What kind of rock does minguzzite form in?+
What is minguzzite used for?+
Find minguzzite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
