Kimzeyite is a rare zirconium-rich member of the garnet group typically found in carbonatite complexes. It is most recognized for its dark, often opaque dodecahedral crystals which can be difficult to distinguish from schorlomite without chemical analysis.
Is this kimzeyite?
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 kimzeyite with a known reference. Kimzeyite 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: light brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: dodecahedral crystals.
Often confused with
Kimzeyite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Kimzeyite leaves light brown, Andradite leaves white; luster reads vitreous on Kimzeyite and adamantine to resinous, dull on Andradite.
How to tell apart: Streak differs, so Kimzeyite leaves light brown, Schorlomite leaves grayish black to red-orange or orange-brown.
Often found alongside kimzeyite
Minerals reported to co-occur with kimzeyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃Zr₂(Al₂Si)O₁₂
- Mohs hardness
- ~7
- Density
- 4.0 g/cm³
- Colors
- Streak
- Light brown
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Cubic
- Crystal habit
- Dodecahedral crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a carbonatite associated with ijolite (Magnet Cove, Arkansas, USA); in a shoshonitic basaltic lava (Stromboli, Italy)
Where rockhounds find kimzeyite
Classic worldwide localities
- Kimzey quarry, Magnet Cove, Hot Spring Co., Arkansas, USA
- Stromboli, Lipari Islands, Italy
Field-hunting tip
Where it forms: In a carbonatite associated with ijolite (Magnet Cove, Arkansas, USA); in a shoshonitic basaltic lava (Stromboli, Italy). If you start seeing apatite, calcite, monticellite in float, you are in the right ground. Typical habit: dodecahedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kimzeyite?+
Where is kimzeyite found?+
What rocks look like kimzeyite?+
What minerals are found with kimzeyite?+
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Find kimzeyite on the map
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