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. Streak: reddish brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 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. 2.5-2.75); 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 to iron-black; luster reads metallic on Omariniite and brilliant to 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 iron-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
- In low-temperature, polymetallic, hydrothermal vein mineralization associated with a diatreme
Where rockhounds find omariniite
Classic worldwide localities
- Argentina
- Bolivia
Field-hunting tip
Where it forms: In low-temperature, polymetallic, hydrothermal vein mineralization associated with a diatreme. If you start seeing putzite, catamarcaite, zincobriartite in float, you are in the right ground. Typical habit: rims or veinlets. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify omariniite?+
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Find omariniite on the map
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