Romanèchite is a significant manganese ore typically found in striking botryoidal or stalactitic masses with a smooth, dark surface. It is often misidentified as 'psilomelane,' which is actually a group name for hydrous manganese oxides rather than a distinct species. Collectors prize it for its dense, metallic luster and unusual rounded growth forms.
Is this romanèchite?
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 romanèchite with a known reference. Romanèchite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Romanèchite leaves a shiny brownish black streak.
- 3Read the lusterHold the specimen under a strong light. Romanèchite typically shows a submetallic to dull luster.
- 4Match the color rangeCompare against the expected color range: black, gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: botryoidal, reniform, massive, stalactitic.
Often confused with
Romanèchite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Romanèchite leaves shiny brownish black, Pyrolusite leaves black; luster reads submetallic to dull on Romanèchite and metallic on Pyrolusite.
How to tell apart: Romanèchite is noticeably harder (Mohs 5-6 vs. 4); streak differs, so Romanèchite leaves shiny brownish black, Manganite leaves dark reddish-brown; luster reads submetallic to dull on Romanèchite and submetallic on Manganite.
Often found alongside romanèchite
Minerals reported to co-occur with romanèchite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ba,H₂O)₂Mn₅O₁₀
- Mohs hardness
- 5-6
- Density
- 4.4-4.8 g/cm³
- Streak
- Shiny Brownish Black
- Luster
- Submetallic to Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Botryoidal, Reniform, Massive, Stalactitic
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Ore
- Host rock
- Sedimentary Manganese Deposits, Hydrothermal Veins
- Typical price
- $5-50 thumbnail, $20-150 cabinet
Where rockhounds find romanèchite
Classic worldwide localities
- Romanèche-Thorins, France
- Sterling Hill, New Jersey, USA
- Kuruman, South Africa
- Deming, New Mexico, USA
- Hartz Mountains, Germany
Field-hunting tip
Look in sedimentary manganese deposits, hydrothermal veins country, the host setting where romanèchite typically forms. If you start seeing pyrolusite, hausmannite, barite in float, you are in the right ground. Field specimens usually show a botryoidal, reniform, massive, stalactitic habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find romanèchite on the map
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