Isomertieite is a rare palladium antimony arsenide mineral typically found as microscopic inclusions within platinum-group element deposits. It is most often identified through reflected light microscopy or microprobe analysis in polished sections from ultramafic complexes. It is a highly sought-after species for specialist mineral collectors of platinum group minerals.
Is this isomertieite?
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 isomertieite with a known reference. Isomertieite sits at Mohs 5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: silver white.
- 5Look at form & habitCrystal system: cubic. Typical habit: anhedral grains, inclusions.
Often confused with
Isomertieite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside isomertieite
Minerals reported to co-occur with isomertieite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pd₁₁Sb₂As₂
- Mohs hardness
- 5.5
- Density
- 10.33 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Anhedral grains, inclusions
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In heavy-metal concentrates from Precambrian iron-precious metal deposits (Itabira district, Brazil)
Where rockhounds find isomertieite
Classic worldwide localities
- Itabira district, Minas Gerais (type locality) and in the Serra Pelada Au–Pd–Pt deposit, Pará, Brazil
- Lac des Iles complex, Ontario, Canada
- Konttijärvi intrusion, northern Finland
- Hope’s Nose, Torquay, Devon, England
- Zlatoust, Ural Mountains, and in the Lukkulaisvaara layered intrusion, Karelia, Russia
- Waiau River, western Southland, New Zealand
Field-hunting tip
Where it forms: In heavy-metal concentrates from Precambrian iron-precious metal deposits (Itabira district, Brazil). If you start seeing arsenopalladinite, atheneite, palladseite in float, you are in the right ground. Typical habit: anhedral grains, inclusions. Train your eye for that shape before scanning the outcrop.






