Reynoldsite is a rare lead-manganese chromate mineral typically found as delicate, acicular, radiating sprays of yellow-orange needles. It is primarily known from select oxidized base-metal mines in Arizona, where it occurs alongside other lead-rich secondary minerals.
Is this reynoldsite?
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 reynoldsite with a known reference. Reynoldsite sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Reynoldsite leaves a dark orange-brown streak.
- 3Read the lusterHold the specimen under a strong light. Reynoldsite typically shows a subadamantine luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-orange, brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: acicular crystals, radiating clusters.
Often confused with
Reynoldsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Reynoldsite is noticeably harder (Mohs 4.5 vs. 3-3.5); streak differs, so Reynoldsite leaves dark orange-brown, Phoenicochroite leaves orange-yellow; luster reads subadamantine on Reynoldsite and adamantine on Phoenicochroite.
How to tell apart: Reynoldsite is noticeably harder (Mohs 4.5 vs. 2.5-3); streak differs, so Reynoldsite leaves dark orange-brown, Vauquelinite leaves greenish-yellow; luster reads subadamantine on Reynoldsite and resinous to adamantine on Vauquelinite.
Often found alongside reynoldsite
Minerals reported to co-occur with reynoldsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂Mn⁺³(CrO₄)₂O(OH)
- Mohs hardness
- 4.5
- Density
- 6.57 g/cm³
- Colors
- Streak
- Dark Orange-brown
- Luster
- Subadamantine
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Acicular Crystals, Radiating Clusters
- Cleavage
- Poor On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Lead-zinc-copper Deposits
Where rockhounds find reynoldsite
Classic worldwide localities
- Red Cloud Mine, Arizona, USA
- Mammoth-St. Anthony Mine, Arizona, USA
Field-hunting tip
Look in oxidized lead-zinc-copper deposits country, the host setting where reynoldsite typically forms. If you start seeing wulfenite, phoenicochroite, diaboleite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiating clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find reynoldsite on the map
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