Jacutingaite is a rare platinum-group mineral typically found as small grains or tabular crystals within the hematite-rich jacutinga ores of Brazil. It is highly valued by mineral collectors for its unique composition and limited occurrence. Collectors should exercise caution as the mineral contains significant amounts of toxic mercury and thallium.
Is this jacutingaite?
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 jacutingaite with a known reference. Jacutingaite 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. Streak: gray [Synthetic].
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, massive, lamellar.
Often confused with
Jacutingaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Palladseite is the harder of the two (Mohs 4.5-5 vs. ~3.5); streak differs, so Jacutingaite leaves gray [synthetic], Palladseite leaves black.
How to tell apart: Jacutingaite is noticeably harder (Mohs ~3.5 vs. 2.5); streak differs, so Jacutingaite leaves gray [synthetic], Temagamite leaves black.
Often found alongside jacutingaite
Minerals reported to co-occur with jacutingaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pt₂HgSe₃
- Mohs hardness
- ~3.5
- Density
- 10.9 g/cm³
- Colors
- Streak
- Gray [Synthetic]
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Tabular crystals, massive, lamellar
- Cleavage
- Very good on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In heavy-mineral concentrate from a friable, hematite-rich auriferous vein that cuts metamorphosed banded iron formation
Where rockhounds find jacutingaite
Classic worldwide localities
- Cauê iron-ore deposit, Itabira District, Minas Gerais, Brazil
Field-hunting tip
Where it forms: In heavy-mineral concentrate from a friable, hematite-rich auriferous vein that cuts metamorphosed banded iron formation. If you start seeing potarite, atheneite, hematite in float, you are in the right ground. Typical habit: tabular crystals, massive, lamellar. Train your eye for that shape before scanning the outcrop.
Common questions
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Find jacutingaite on the map
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