Kuzelite is a rare layered double hydroxide mineral typically found in environments associated with the hydration of industrial waste like blast furnace slag or concrete. Collectors should look for delicate, white to colorless hexagonal plates or radiating rosettes in cavities of anthropogenic materials. It is a scientifically significant mineral for understanding mineral crystallization in artificial geological settings.

Hardness

Mohs

Luster

Pearly

Streak

White

Transparency

Translucent

mineralrareHydrotalcite Supergroup family

Kuzelite

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

Is this kuzelite?

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 kuzelite with a known reference. Kuzelite 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. Kuzelite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Kuzelite 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 hexagonal crystals, rosettes, or incrustations.

Often confused with

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

mineral

Ettringite

Mohs 2

How to tell apart: Luster reads pearly on Kuzelite and vitreous on Ettringite.

Often found alongside kuzelite

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

All properties

Chemical formula: Ca₄Al₂(OH)₁₂(SO₄)·6H₂O
Mohs hardness: 2
Density: 2.05 g/cm³
Colors: White Colorless Pale Yellow
Streak: White
Luster: Pearly
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Platy Hexagonal Crystals, Rosettes, Or Incrustations
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Altered Calcium-rich Industrial Waste Sites, Cement Hydration Zones
Typical price: $20-100 per specimen

Where rockhounds find kuzelite

Classic worldwide localities

Kuzel mine, Germany
Cava del Ferro, Italy
Upper Merion Township, USA

Field-hunting tip

Look in altered calcium-rich industrial waste sites, cement hydration zones country — that is the host setting where kuzelite typically forms. If you start seeing ettringite, portlandite, gypsum in float, you are in the right ground. Field specimens usually show a platy hexagonal crystals, rosettes, or incrustations habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kuzelite?+

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

Where is kuzelite found?+

Notable localities include Kuzel mine, Germany; Cava del Ferro, Italy; Upper Merion Township, USA.

How much is kuzelite worth?+

Typical asking prices fall in the range of $20-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like kuzelite?+

Kuzelite is most often confused with Ettringite, Hydrocalumite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kuzelite?+

Kuzelite commonly co-occurs with Ettringite, Portlandite, Gypsum, Calcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kuzelite form in?+

Kuzelite typically forms in altered calcium-rich industrial waste sites, cement hydration zones. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kuzelite used for?+

Kuzelite is used in collector.

Find kuzelite on the map

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