Ominelite is a rare member of the sapphirine group, primarily occurring in high-grade metamorphic environments. It is visually similar to sapphirine but distinguished by its distinct chemical composition and specific locality origins. Collectors typically find it as small, dark blue, tabular crystals embedded in metamorphic assemblages.
Is this ominelite?
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 ominelite with a known reference. Ominelite sits at Mohs ~7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: blue.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: anhedral grains, equant grains.
Often confused with
Ominelite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside ominelite
Minerals reported to co-occur with ominelite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeAl₃O₂(BO₃)(SiO₄)
- Mohs hardness
- ~7
- Density
- 3.169 g/cm³
- Colors
- Streak
- Pale blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Anhedral grains, equant grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Research
- Host rock
- In porphyritic granite and granodiorite (Japan); in borosilicate-bearing veinlets cutting leucogranulite (Czech Republic)
Where rockhounds find ominelite
Classic worldwide localities
- Omine Mountains near the misen River at Tenkawa, Yoshio, Nara Prefecture, Japan (type locality)
Field-hunting tip
Where it forms: In porphyritic granite and granodiorite (Japan); in borosilicate-bearing veinlets cutting leucogranulite (Czech Republic). If you start seeing sekaninaite, garnet, biotite in float, you are in the right ground. Typical habit: anhedral grains, equant grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ominelite?+
Where is ominelite found?+
What rocks look like ominelite?+
What minerals are found with ominelite?+
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What is ominelite used for?+
Find ominelite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
