Zaccagnaite is a rare zinc-aluminum layered double hydroxide mineral that typically forms thin, translucent, hexagonal tabular crystals. It is most frequently identified in museum-grade specimens from marble quarries where it occurs as delicate clusters or coatings associated with zinc-bearing mineralization.
Is this zaccagnaite?
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 zaccagnaite with a known reference. Zaccagnaite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Zaccagnaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Zaccagnaite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, tabular hexagonal plates.
Often confused with
Zaccagnaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside zaccagnaite
Minerals reported to co-occur with zaccagnaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₄Al₂(OH)₁₂(CO₃)·3H₂O
- Mohs hardness
- 2
- Density
- 2.23 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals, Tabular Hexagonal Plates
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Marble
- Typical price
- $20-150 thumbnail
Where rockhounds find zaccagnaite
Classic worldwide localities
- Carrara, Tuscany, Italy
- Lavrion, Greece
- Tsumeb, Namibia
Field-hunting tip
Look in hydrothermal veins in marble country — that is the host setting where zaccagnaite typically forms. If you start seeing smithsonite, calcite, dolomite in float, you are in the right ground. Field specimens usually show a platy crystals, tabular hexagonal plates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find zaccagnaite on the map
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