Omsite is a rare nickel iron antimony hydroxide, typically bright to amber-yellow. It occurs in narrow, crystal-lined fractures cutting massive siderite-bearing rock. It was first described from Correc d'en Llinassos, near the village of Oms, Pyrénées-Orientales Department, France.
Is this omsite?
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 omsite with a known reference. Omsite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Omsite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Omsite typically shows a vitreous to resinous luster.
- 4Match the color rangeCompare against the expected color range: amber-yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: microcrystalline aggregates.
Often confused with
Omsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Omsite leaves pale yellow, Retgersite leaves pale green; luster reads vitreous to resinous on Omsite and vitreous on Retgersite.
How to tell apart: Streak differs, so Omsite leaves pale yellow, Morenosite leaves white; luster reads vitreous to resinous on Omsite and vitreous on Morenosite.
Often found alongside omsite
Minerals reported to co-occur with omsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₂Fe³⁺(OH)₆[Sb(OH)₆]
- Mohs hardness
- 2
- Density
- 3.378 g/cm³
- Colors
- Streak
- Pale Yellow
- Luster
- Vitreous to Resinous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Microcrystalline Aggregates
- Cleavage
- Poor On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Nickel-sulfide Ore Deposits
Where rockhounds find omsite
Classic worldwide localities
- Correc d'en Llinassos, Pyrénées-Orientales Department, France
Field-hunting tip
Look in oxidized nickel-sulfide ore deposits country, the host setting where omsite typically forms. If you start seeing gersdorffite, annabergite, millerite in float, you are in the right ground. Field specimens usually show a microcrystalline aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify omsite?+
Where is omsite found?+
Is omsite safe to handle?+
What rocks look like omsite?+
What minerals are found with omsite?+
What kind of rock does omsite form in?+
What is omsite used for?+
Find omsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
