Omariniite is a rare copper iron zinc sulfide that forms orange-brown rims or veinlets. It occurs in low-temperature, polymetallic, hydrothermal vein mineralization associated with a diatreme. It was first described from near the La Rosario vein of the Capillitas deposit, Catamarca Province, Argentina.
Is this omariniite?
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 omariniite with a known reference. Omariniite 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. Omariniite leaves a reddish brown streak.
- 3Read the lusterHold the specimen under a strong light. Omariniite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, dark gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: rims or veinlets.
Often confused with
Omariniite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Omariniite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so Omariniite leaves reddish brown, Galena leaves lead-gray.
How to tell apart: Streak differs, so Omariniite leaves reddish brown, Bournonite leaves steel-gray; luster reads metallic on Omariniite and dull on Bournonite.
How to tell apart: Omariniite is noticeably harder (Mohs 3.5 vs. 2-2.5); streak differs, so Omariniite leaves reddish brown, Stephanite leaves black.
Often found alongside omariniite
Minerals reported to co-occur with omariniite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₈Fe₂ZnGe₂S₁₂
- Mohs hardness
- 3.5
- Density
- 4.319 g/cm³
- Streak
- Reddish Brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Rims or Veinlets
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
Where rockhounds find omariniite
Classic worldwide localities
- Argentina
- Bolivia
Field-hunting tip
Look in hydrothermal veins country, the host setting where omariniite typically forms. If you start seeing galena, sphalerite, pyrite in float, you are in the right ground. Field specimens usually show a rims or veinlets habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find omariniite on the map
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