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.

Hardness

Mohs

Luster

Pearly

Streak

White

Transparency

Translucent

mineralrareHydrotalcite Group family

Zaccagnaite

Hardness: 2
Luster: Pearly
Streak: White
Transparency: Translucent

No image

Is this zaccagnaite?

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 zaccagnaite with a known reference. Zaccagnaite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Zaccagnaite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Zaccagnaite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: white, colorless, pale yellow.
5
Look at form & habit
Crystal 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
Colors: White Colorless Pale Yellow
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, 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

How do you identify zaccagnaite?+

Mohs hardness is 2. It typically shows a pearly luster. The streak is white. Common colors include white, colorless, pale yellow.

Where is zaccagnaite found?+

Notable localities include Carrara, Tuscany, Italy; Lavrion, Greece; Tsumeb, Namibia.

How much is zaccagnaite worth?+

Typical asking prices fall in the range of $20-150 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like zaccagnaite?+

Zaccagnaite is most often confused with Hydrotalcite, Woodwardite, Meixnerite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with zaccagnaite?+

Zaccagnaite commonly co-occurs with Smithsonite, Calcite, Dolomite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does zaccagnaite form in?+

Zaccagnaite typically forms in hydrothermal veins in marble. Working float back to the host body is the standard way to chase a fresh occurrence.

What is zaccagnaite used for?+

Zaccagnaite is used in collector.

Find zaccagnaite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.