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 — 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 — 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 — that is 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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