Zirkelite is a rare complex oxide mineral typically found in carbonatites and alkaline igneous complexes. Collectors look for its dark, often lustrous octahedral crystals, though it is frequently found as irregular grains associated with baddeleyite and other titanium-rich minerals.
Is this zirkelite?
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 zirkelite with a known reference. Zirkelite sits at Mohs 5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish gray.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous.
- 4Match the color rangeCompare against the expected color range: black, reddish brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: crystalline, metamict, pseudo cubic.
Often confused with
Zirkelite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Zirkelite leaves brownish gray, Pyrochlore leaves brown; luster reads resinous on Zirkelite and vitreous to resinous on Pyrochlore.
How to tell apart: Baddeleyite is the harder of the two (Mohs 6.5 vs. 5.5); streak differs, so Zirkelite leaves brownish gray, Baddeleyite leaves white to brownish white; luster reads resinous on Zirkelite and greasy to vitreous; nearly submetallic in black crystals on Baddeleyite.
How to tell apart: Streak differs, so Zirkelite leaves brownish gray, Perovskite leaves white to grayish white; luster reads resinous on Zirkelite and adamantine to metallic; may be dull on Perovskite.
Often found alongside zirkelite
Minerals reported to co-occur with zirkelite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ti,Ca,Zr)O₂-x
- Mohs hardness
- 5.5
- Density
- 4.741 g/cm³
- Colors
- Streak
- Brownish gray
- Luster
- Resinous
- Transparency
- Opaque, transparent in very thin fragments
- Crystal system
- Cubic
- Crystal habit
- Crystalline, metamict, pseudo cubic
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a magnetite-pyroxenite carbonatite (Jacupiranga, Brazil); a late-stage differentiate in a layered intrusion (Rhum, Scotland)
Where rockhounds find zirkelite
Classic worldwide localities
- Jacupiranga carbonatite, São Paulo, Brazil
- St. Kilda, Outer Hebrides, and Rhum, Inner Hebrides, Scotland
- Vouriyarvi and Kovdor massifs, and in the Sevlyavr carbonatite complex, Kola Peninsula, Russia
- Arbarastkh massif, Aldan Shield, Sakha, Russia
- Phalaborwa, Transvaal, South Africa
- Walawada, Sri Lanka
Field-hunting tip
Where it forms: In a magnetite-pyroxenite carbonatite (Jacupiranga, Brazil); a late-stage differentiate in a layered intrusion (Rhum, Scotland). If you start seeing perovskite, baddeleyite in float, you are in the right ground. Typical habit: crystalline, metamict, pseudo cubic. Train your eye for that shape before scanning the outcrop.
Common questions
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Find zirkelite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
