Chlorbartonite is a rare potassium iron sulfide chloride mineral discovered in alkaline massifs. It typically appears as dark green to black submetallic grains or platy crystals often found within the core of magnetite-rich rocks. Collectors prize it for its unique chemical composition related to the baronite group.
Is this chlorbartonite?
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 chlorbartonite with a known reference. Chlorbartonite sits at Mohs 3-3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Chlorbartonite leaves a greenish-black streak.
- 3Read the lusterHold the specimen under a strong light. Chlorbartonite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: dark green, olive green, black.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, granular aggregates.
Often confused with
Chlorbartonite vs. its common look-alikes — and how to tell them apart in the field.

How to tell apart: Streak differs — Chlorbartonite leaves greenish-black, Bartonite leaves dark reddish-brown; luster reads submetallic on Chlorbartonite and metallic on Bartonite.

How to tell apart: Chlorbartonite is noticeably harder (Mohs 3-3.5 vs. 1); streak differs — Chlorbartonite leaves greenish-black, Valleriite leaves black; luster reads submetallic on Chlorbartonite and metallic on Valleriite.
Often found alongside chlorbartonite
Minerals reported to co-occur with chlorbartonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₆Fe₂₄S₂₆Cl
- Mohs hardness
- 3-3.5
- Density
- 3.17 g/cm³
- Streak
- Greenish-black
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals, Granular Aggregates
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find chlorbartonite
Classic worldwide localities
- Kovdor Massif, Kola Peninsula, Russia
Field-hunting tip
Look in alkaline igneous rocks country — that is the host setting where chlorbartonite typically forms. If you start seeing magnetite, phlogopite, forsterite in float, you are in the right ground. Field specimens usually show a platy crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.




