Fraipontite is a rare zinc-rich member of the serpentine group typically found in the oxidation zones of zinc-bearing ore bodies. It usually occurs as delicate, platy, or earthy masses, often displaying a soft pearly luster that distinguishes it from common smithsonite.
Is this fraipontite?
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 fraipontite with a known reference. Fraipontite 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. Fraipontite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fraipontite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, pale yellow, green, blue-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy, earthy, massive.
Often confused with
Fraipontite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads pearly on Fraipontite and vitreous on Chrysocolla.
How to tell apart: Smithsonite is the harder of the two (Mohs 4-4.5 vs. 2-3); luster reads pearly on Fraipontite and vitreous on Smithsonite.
How to tell apart: Hemimorphite is the harder of the two (Mohs 4.5-5 vs. 2-3); luster reads pearly on Fraipontite and vitreous on Hemimorphite.
Often found alongside fraipontite
Minerals reported to co-occur with fraipontite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Zn,Al)₃(Si,Al)₂O₅(OH)₄
- Mohs hardness
- 2-3
- Density
- 2.8-3.1 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy, Earthy, Massive
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Zinc Deposits
- Typical price
- $20-150 for micro to thumbnail specimens
Where rockhounds find fraipontite
Classic worldwide localities
- Fraipont, Belgium
- Mapimi, Mexico
- Tsumeb, Namibia
Field-hunting tip
Look in oxidized zones of zinc deposits country, the host setting where fraipontite typically forms. If you start seeing smithsonite, willemite, hemimorphite in float, you are in the right ground. Field specimens usually show a platy, earthy, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find fraipontite on the map
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