Bartonite is a rare potassium-iron sulfide mineral typically found as small, metallic grains within alkaline igneous rocks or evaporite suites. Collectors generally find it as an inclusion or interstitial component, requiring microscopic identification or analytical verification to distinguish from other iron sulfides like pyrrhotite.
Is this bartonite?
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 bartonite with a known reference. Bartonite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bartonite leaves a dark reddish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Bartonite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, bronze-brown.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: massive, granular, or anhedral grains.
Often confused with
Bartonite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Bartonite leaves dark reddish-brown, Pyrrhotite leaves dark grey to black.
How to tell apart: Streak differs — Bartonite leaves dark reddish-brown, Djerfisherite leaves black.
How to tell apart: Streak differs — Bartonite leaves dark reddish-brown, Pentlandite leaves light bronze-brown.
Often found alongside bartonite
Minerals reported to co-occur with bartonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₆Fe₂₀S₂₆Cl
- Mohs hardness
- 3.5
- Density
- 3.37 g/cm³
- Colors
- Streak
- Dark Reddish-brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Massive, Granular, Or Anhedral Grains
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Complexes and Evaporite Deposits
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find bartonite
Classic worldwide localities
- Kovdor Massif, Russia
- Green River Formation, USA
- Mont Saint-Hilaire, Canada
Field-hunting tip
Look in alkaline igneous complexes and evaporite deposits country — that is the host setting where bartonite typically forms. If you start seeing pyrrhotite, djerfisherite, halite in float, you are in the right ground. Field specimens usually show a massive, granular, or anhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find bartonite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
