Bixbyite is a distinct manganese iron oxide that typically forms as brilliant, metallic black cubo-octahedral crystals. It is most famous to collectors for the exceptional specimens found in the rhyolite cavities of the Thomas Range in Utah. It is highly valued for its sharp crystal faces and high luster.
Is this bixbyite?
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 bixbyite with a known reference. Bixbyite sits at Mohs 6-6.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bixbyite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Bixbyite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: cubic. Typical habit: cubo-octahedral crystals, often striated.
Often confused with
Bixbyite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside bixbyite
Minerals reported to co-occur with bixbyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mn,Fe)₂O₃
- Mohs hardness
- 6-6.5
- Density
- 4.9-5.0 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Cubo-octahedral Crystals, Often Striated
- Cleavage
- Poor On {111}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Rhyolitic Volcanic Rocks, Manganese-rich Metamorphic Rocks
- Typical price
- $20-200 for thumbnail to small cabinet specimens
Where rockhounds find bixbyite
1 mapped spotsClassic worldwide localities
- Thomas Range, Utah, USA
- Sitapar, India
- Kuruman, South Africa
- Wessels Mine, South Africa
Field-hunting tip
Look in rhyolitic volcanic rocks, manganese-rich metamorphic rocks country — that is the host setting where bixbyite typically forms. If you start seeing topaz, beryl, spessartine in float, you are in the right ground. Field specimens usually show a cubo-octahedral crystals, often striated habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah — start trip planning there.
Common questions
How do you identify bixbyite?+
Where is bixbyite found?+
Can I find bixbyite in the United States?+
How much is bixbyite worth?+
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Find bixbyite on the map
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