Klaprothite is a rare sodium uranium sulfate, typically yellowish green to greenish yellow. It was approved as a distinct mineral species in 2015. It was first described from Blue Lizard mine, Red Canyon, White Canyon district, San Juan County, Utah, USA.
Is this klaprothite?
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 klaprothite with a known reference. Klaprothite sits at Mohs ~2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale yellow-green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellowish green, greenish yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, granular, or rarely as indistinct prismatic crystals.
Often confused with
Klaprothite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Klaprothite leaves pale yellow-green, Wittichenite leaves black; luster reads vitreous on Klaprothite and metallic on Wittichenite.
How to tell apart: Streak differs, so Klaprothite leaves pale yellow-green, Tetrahedrite leaves black to brown; luster reads vitreous on Klaprothite and metallic, commonly splendent on Tetrahedrite.
How to tell apart: Streak differs, so Klaprothite leaves pale yellow-green, Bismuthinite leaves lead-gray; luster reads vitreous on Klaprothite and metallic on Bismuthinite.
Often found alongside klaprothite
Minerals reported to co-occur with klaprothite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₆(UO₂)(SO₄)₄(H₂O)₄
- Mohs hardness
- ~2.5
- Density
- 2.90 g/cm³
- Streak
- Pale yellow-green
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, granular, or rarely as indistinct prismatic crystals
- Cleavage
- Perfect on {100} and {001}
- Fluorescence
- Bright bluish green fluorescence under SW & LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As efflorescent crusts on mine walls, formed by hydration-oxidation weathering of primary uranium minerals (mainly uraninite) by acidic solutions from the decomposition of sulfides
Where rockhounds find klaprothite
Classic worldwide localities
- Blue Lizard mine, Red Canyon, White Canyon district, San Juan County, Utah, USA
Field-hunting tip
Where it forms: As efflorescent crusts on mine walls, formed by hydration-oxidation weathering of primary uranium minerals (mainly uraninite) by acidic solutions from the decomposition of sulfides. If you start seeing blödite, bluelizardite, bobcookite in float, you are in the right ground. Typical habit: massive, granular, or rarely as indistinct prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify klaprothite?+
Where is klaprothite found?+
Is klaprothite safe to handle?+
What rocks look like klaprothite?+
What minerals are found with klaprothite?+
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Find klaprothite on the map
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