Pyrolusite is the primary ore of manganese, frequently found as beautiful dendritic, fern-like patterns on fracture surfaces of rocks. It is characterized by its metallic luster, heavy feel, and distinctively black, powdery streak when scratched.
Is this pyrolusite?
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 pyrolusite with a known reference. Pyrolusite sits at Mohs 6-6.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pyrolusite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Pyrolusite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, bluish-black, dark gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: often radiating, fibrous, or dendritic; sometimes massive or powdery.
Often confused with
Pyrolusite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Pyrolusite is noticeably harder (Mohs 6-6.5 vs. 4); streak differs, so Pyrolusite leaves black, Manganite leaves dark reddish-brown; luster reads metallic on Pyrolusite and submetallic on Manganite.
How to tell apart: Streak differs, so Pyrolusite leaves black, Romanèchite leaves shiny brownish black; luster reads metallic on Pyrolusite and submetallic to dull on Romanèchite.
How to tell apart: Streak differs, so Pyrolusite leaves black, Iron Ore leaves reddish-brown to black; luster reads metallic on Pyrolusite and metallic to submetallic on Iron Ore.
Often found alongside pyrolusite
Minerals reported to co-occur with pyrolusite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnO₂
- Mohs hardness
- 6-6.5
- Density
- 4.4-5.1 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Often Radiating, Fibrous, Or Dendritic; Sometimes Massive or Powdery
- Cleavage
- Perfect
- Rarity
- Common
- Uses
- Industrial, Collector, Ore of Manganese
- Host rock
- Sedimentary Manganese Deposits, Hydrothermal Veins, And Oxidation Zones
- Typical price
- $10-50 for small cabinet specimens
Where rockhounds find pyrolusite
31 mapped spotsClassic worldwide localities
- Ilmenau, Germany
- Groote Eylandt, Australia
- Minas Gerais, Brazil
- Batesville, Arkansas, USA
U.S. states with pyrolusite
Each link opens a state-specific list of mapped rockhounding spots that produce pyrolusite.
Field-hunting tip
Look in sedimentary manganese deposits, hydrothermal veins, and oxidation zones country, the host setting where pyrolusite typically forms. If you start seeing manganite, psilomelane, goethite in float, you are in the right ground. Field specimens usually show a often radiating, fibrous, or dendritic; sometimes massive or powdery habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, California, Idaho. Start trip planning there.
Common questions
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Find pyrolusite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
