Baddeleyite is a rare zirconium oxide mineral primarily found in alkaline igneous environments like carbonatites. Collectors typically look for its distinctively twinned, dark-colored monoclinic crystals often associated with heavy accessory minerals.
Is this baddeleyite?
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 baddeleyite with a known reference. Baddeleyite sits at Mohs 6.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white to brownish white.
- 3Read the lusterHold the specimen under a strong light. Luster: greasy to vitreous; nearly submetallic in black crystals.
- 4Match the color rangeCompare against the expected color range: brown, brownish black, colorless, green, greenish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crystalline, tabular.
Often confused with
Baddeleyite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads greasy to vitreous; nearly submetallic in black crystals on Baddeleyite and adamantine to adamantine metallic, splendent; may be greasy on fractures on Cassiterite.
How to tell apart: Streak differs, so Baddeleyite leaves white to brownish white, Rutile leaves pale brown, yellowish brown; gray, greenish black with high nb–ta; luster reads greasy to vitreous; nearly submetallic in black crystals on Baddeleyite and adamantine to submetallic on Rutile.
How to tell apart: Zircon is the harder of the two (Mohs 7.5 vs. 6.5); luster reads greasy to vitreous; nearly submetallic in black crystals on Baddeleyite and vitreous to adamantine; greasy when metamict on Zircon.
Often found alongside baddeleyite
Minerals reported to co-occur with baddeleyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- ZrO₂
- Mohs hardness
- 6.5
- Density
- 5.40-6.02 g/cm³
- Streak
- White to brownish white
- Luster
- Greasy to vitreous; nearly submetallic in black crystals
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Crystalline, tabular
- Cleavage
- {001} nearly perfect, {010} and {110} less perfect
- Rarity
- Uncommon
- Uses
- Ore of zirconium, Refractory materials, Collector
- Host rock
- An accessory mineral in carbonatites and kimberlites; in syenites, diabases, gabbros, anorthosites; detrital in gem gravels
Where rockhounds find baddeleyite
Classic worldwide localities
- Bozeman, Gallatin Co., Montana, USA
- Rakwana and Balangoda, Sri Lanka
- Monte Somma, Campania, Italy
- Kovdor massif, and in the Gulinskii massif, the Vuoriyarvi carbonatite complex, and the Imandrovsky layered intrusion, Kola Peninsula, Russia
- Lukkulaisvaara layered intrusion, Karelia, Russia
- Jacupiranga mine, São Paulo, and at Poços de Caldas, Minas Gerais, Brazil
Field-hunting tip
Where it forms: An accessory mineral in carbonatites and kimberlites; in syenites, diabases, gabbros, anorthosites; detrital in gem gravels. If you start seeing ilmenite, zirkelite, apatite in float, you are in the right ground. Typical habit: crystalline, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
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Find baddeleyite on the map
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