Economic Importance
Kimberlites are the most important source of primary diamonds. Many kimberlite pipes also produce rich alluvial or eluvial diamond placer deposits. Only about 1 in 200 kimberlite pipes contain gem-quality diamonds.
The deposits occurring at Kimberley, South Africa were the first recognized and the source of the name. The Kimberley diamonds were originally found in weathered kimberlite which was colored yellow by limonite, and so was called yellow ground. Deeper workings encountered less altered rock, serpentinized kimberlite, which miners call blue ground.
See also Udachnaya pipe.
The blue and yellow ground were both prolific producers of diamonds. After the yellow ground had been exhausted, miners in the late 19th century accidentally cut into the blue ground and found gem quality diamonds in quantity. The economic importance of the time is that with flood of diamonds being found, the miners were undercutting each other's price of the diamonds and eventually decreased the diamonds' value down to cost in a short time.
Read more about this topic: Kimberlite
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