Orthobrannerite is a rare uranium-bearing mineral often found as dark, prismatic crystals in pegmatite environments. Due to its high radioactivity and rarity, it is sought after specifically by advanced mineral collectors of uranium species.
Is this orthobrannerite?
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 orthobrannerite with a known reference. Orthobrannerite sits at Mohs 4-5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Orthobrannerite leaves a dark brown to black streak.
- 3Read the lusterHold the specimen under a strong light. Orthobrannerite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: black, brownish-black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals.
Often confused with
Orthobrannerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Orthobrannerite leaves dark brown to black, Brannerite leaves brownish-yellow; luster reads adamantine on Orthobrannerite and vitreous on Brannerite.
How to tell apart: Rutile is the harder of the two (Mohs 6-6.5 vs. 4-5); streak differs, so Orthobrannerite leaves dark brown to black, Rutile leaves pale brown to yellow; luster reads adamantine on Orthobrannerite and metallic to adamantine on Rutile.
How to tell apart: Streak differs, so Orthobrannerite leaves dark brown to black, Manaccanite leaves black; luster reads adamantine on Orthobrannerite and submetallic on Manaccanite.
Often found alongside orthobrannerite
Minerals reported to co-occur with orthobrannerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- UTi₂O₆
- Mohs hardness
- 4-5
- Density
- 5.4-5.5 g/cm³
- Colors
- Streak
- Dark Brown to Black
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
Where rockhounds find orthobrannerite
Classic worldwide localities
- Undefined localities in Yunan and Szechwan Provinces, China
Field-hunting tip
Look in granite pegmatites country, the host setting where orthobrannerite typically forms. If you start seeing quartz, albite, muscovite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify orthobrannerite?+
Where is orthobrannerite found?+
Is orthobrannerite safe to handle?+
What rocks look like orthobrannerite?+
What minerals are found with orthobrannerite?+
What kind of rock does orthobrannerite form in?+
What is orthobrannerite used for?+
Find orthobrannerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
