from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A rock formation in South Africa containing peridotite, in which diamonds are formed.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A variety of peridotite containing a high proportion of carbon dioxide; often contains diamonds.
from The Century Dictionary and Cyclopedia
- n. In petrography, a dense porphyritic peridotite, occurring at Kimberley, South Africa, partly serpentinized with phenocrysts of olivin and with a few of biotite, bronzite, ilmenite, perovskite, and pyrope.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a rare type of peridotite that sometimes contains diamonds; found in South Africa and Siberia
He used an electron microprobe to analyze geological structures called kimberlite pipes — the places you occasionally (but not often) find diamonds — and discovered that the presence of chromite, ilmenite, and high-chrome, low-calcium garnet did indeed predict a rich strike.
The diamonds at Kimberley are found in a blue earth, technically known as kimberlite and commonly called "blue ground."
Most diamonds are found near the place where deep Earth processes blasted them to the surface in special rock material called kimberlite (named for Kimberley, South Africa).
A combination of UG bulk sampling and LDD mini-bulk sampling is required to rigorously evaluate such a large kimberlite, which is buried under some 100 metres of glacial overburden.
These are deep, vertical shafts, usually filled with a mixture of rock types, including the diamond-bearing rock called kimberlite (Figure 1).
Meanwhile, the machines used to dig diamonds out of kimberlite ore can have hefty carbon footprints.
But Fipke and Blusson surmised that the indicators De Beers found had in fact been dragged far from the kimberlite pipe eons ago by a passing glacier.
It was 1991, and he had found a kimberlite pipe (buried under 30 feet of glaciated sediment) with a concentration of 68 carats per 100 tons — the first Canadian diamonds ever found.
He found half a dozen, but like 98 percent of the kimberlite formations in the world, they didn't contain diamonds in commercially viable quantities.
(In kimberlite pipes that have gem-quality stones in commercial quantities, a concentration of 1 carat — 0.2 grams — per 100 tons can be profitable.)