Rongibbsite is a rare secondary lead-aluminum silicate mineral found in oxidized base metal deposits. It typically occurs as small, colorless, platy or micaceous crystals often associated with other lead-bearing minerals in hydrothermal environments.
Is this rongibbsite?
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 rongibbsite with a known reference. Rongibbsite sits at Mohs ~5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals.
Often confused with
Rongibbsite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside rongibbsite
Minerals reported to co-occur with rongibbsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂(AlSi₄)O₁₁(OH)
- Mohs hardness
- ~5
- Density
- 4.43 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy crystals
- Cleavage
- Perfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- The product of the weathering of a lead and copper-bearing quartz vein in gneiss
Where rockhounds find rongibbsite
Classic worldwide localities
- Big Horn Mountains, Maricopa County, Arizona, USA
Field-hunting tip
Where it forms: The product of the weathering of a lead and copper-bearing quartz vein in gneiss. If you start seeing wickenburgite, fornacite, mimetite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify rongibbsite?+
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Is rongibbsite safe to handle?+
What rocks look like rongibbsite?+
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Find rongibbsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
