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.

Hardness

Mohs

Luster

Subadamantine

Streak

White

Transparency

Opaque

mineralrareGarnet Group family

Kimzeyite

Hardness: 7
Luster: Subadamantine
Streak: White
Transparency: Opaque

Is this kimzeyite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch kimzeyite with a known reference. Kimzeyite sits at Mohs 7 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kimzeyite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Kimzeyite typically shows a subadamantine luster.
4
Match the color range
Compare against the expected color range: dark brown, black, reddish brown.
5
Look at form & habit
Crystal system: cubic. Typical habit: dodecahedral crystals.

Often confused with

Kimzeyite vs. its common look-alikes — and how to tell them apart in the field.

mineral

Andradite

Mohs 6.5-7.5

How to tell apart: Luster reads subadamantine on Kimzeyite and vitreous on Andradite.

How to tell apart: Luster reads subadamantine on Kimzeyite and vitreous on Schorlomite.

Compare →

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: Ca₃(Zr,Ti)₂(Si,Al,Fe³⁺)₃O₁₂
Mohs hardness: 7
Density: 4.15-4.25 g/cm³
Colors: Dark Brown Black Reddish Brown
Streak: White
Luster: Subadamantine
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Dodecahedral Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Carbonatite
Typical price: $50-300 per specimen

Where rockhounds find kimzeyite

Classic worldwide localities

Magnet Cove, Arkansas, USA

Field-hunting tip

Look in carbonatite country — that is the host setting where kimzeyite typically forms. If you start seeing magnetite, monticellite, apatite in float, you are in the right ground. Field specimens usually show a dodecahedral crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kimzeyite?+

Mohs hardness is 7. It typically shows a subadamantine luster. The streak is white. Common colors include dark brown, black, reddish brown.

Where is kimzeyite found?+

Notable localities include Magnet Cove, Arkansas, USA.

How much is kimzeyite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like kimzeyite?+

Kimzeyite is most often confused with Andradite, Schorlomite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kimzeyite?+

Kimzeyite commonly co-occurs with Magnetite, Monticellite, Apatite, Perovskite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kimzeyite form in?+

Kimzeyite typically forms in carbonatite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kimzeyite used for?+

Kimzeyite is used in collector.

Find kimzeyite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.