Kimberlite
Kimberlite is igneous (ultramafic, volatile-rich). In the hand, it rates 2.5 to 5 (altered, variable) on the Mohs scale, and it runs blue-gray ('blue ground') and green-gray. Crumbly blue-gray mottled rock stuffed with foreign crumbs, olivine, purple-red garnets, black ilmenite, the chaotic elevator rock of diamond pipes.
The geology.
Kimberlite carries the formula . It belongs to the, system. Catalogues list it as igneous (ultramafic, volatile-rich).
It sits at 2.5 to 5 (altered, variable) on the Mohs scale. The surface reads dull, greasy. Light behaviour is opaque. Specific gravity runs 2.6 to 3.0. The streak is,. It breaks with crumbly, uneven fracture.
Crumbly blue-gray mottled rock stuffed with foreign crumbs, olivine, purple-red garnets, black ilmenite, the chaotic elevator rock of diamond pipes.
It reaches buyers as drill-core pieces, mine specimens or matrix with garnet or diamond.
The origins.
Volcanic pipes in ancient cratons: Kimberley (South Africa, namesake), Russia, Botswana, Arkansas's Crater of Diamonds (USA).
On value, the database notes: inexpensive as rock; diamond-bearing specimens are another universe.
Traditional associations.
In energy work traditions, kimberlite has little lore of its own; it borrows glamour as the diamond's mother rock.
We keep this section because people ask. It sits below the geology on purpose, and none of it describes something the stone does.
Spotting the real thing.
Crumbly blue-gray mottled rock stuffed with foreign crumbs, olivine, purple-red garnets, black ilmenite, the chaotic elevator rock of diamond pipes.
'Kimberlite with diamond' tourist pieces often carry glued-in CZ or quartz, real in-matrix diamonds are museum material.
| Looks like | How to tell them apart |
|---|---|
| Serpentinite | Serpentinite is waxier and more coherent; kimberlite is a crumbly mixed breccia with visible xenocrysts |
| Basalt | Basalt is hard and uniform; kimberlite is soft, greasy, and chunky |
| Lamproite | The Argyle-style cousin, distinguishing them is lab geology, not hand-lens work |
At-home tests.
Before anyone talks you into a lab report, these are the checks worth doing yourself on kimberlite.
| Test | What you should see |
|---|---|
| By eye | Mottled texture with rounded foreign crystals |
| Scratch check | Soft and crumbly, often scratchable with a knife |
| By eye | Pyrope garnet and ilmenite 'indicator minerals' inside |
Stop short of anything that leaves a mark. A gemologist can answer the rest without damaging the stone.
Care & handling.
At 2.5 to 5 (altered, variable) on the Mohs scale this is a soft material. Keep it as a display piece, store it apart from harder stones, and skip daily-wear settings.
It breaks with crumbly, uneven fracture, which is worth knowing before you set it or drop it.
Skip the ultrasonic. Lukewarm water, mild soap and a soft cloth handle routine cleaning without risk.
A deeper look.
Extended detail on composition, sourcing, authentication and market value.
The physical record
The formula on record is . Crystal system:,. Specific gravity: 2.6 to 3.0. Streak:,. Cleavage and fracture: Crumbly, uneven fracture.
How it reaches the market
Volcanic pipes in ancient cratons: Kimberley (South Africa, namesake), Russia, Botswana, Arkansas's Crater of Diamonds (USA).
What it gets confused with
Serpentinite: Serpentinite is waxier and more coherent; kimberlite is a crumbly mixed breccia with visible xenocrysts. Basalt: Basalt is hard and uniform; kimberlite is soft, greasy, and chunky. Lamproite: The Argyle-style cousin, distinguishing them is lab geology, not hand-lens work.
What it is worth
Inexpensive as rock; diamond-bearing specimens are another universe.
Where buyers get caught
'Kimberlite with diamond' tourist pieces often carry glued-in CZ or quartz, real in-matrix diamonds are museum material.
One more thing
Kimberlite eruptions rocketed from 150+ km deep at highway speeds, the only natural express service delivering diamonds to the surface.
An education-first guide.
We do not carry kimberlite. This page exists because the question comes up and the honest answer is worth writing down, whether or not there is anything here to sell you.
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