Magmatic Ore Deposits - Metals and Society: An Introduction to Economic Geology - page 69

Fig. 3.18 Two views of the Palabora open pit - a major Cu-rich multi-element deposit hosted in
an alkali intrusion in South Africa
Strictly speaking diamonds in kimberlites are not truly magmatic. They are
thought to be xenocrysts that were plucked from the sub-continental lithospheric
mantle as the kimberlite magma ascended from its deep source to the surface.
Diamond is the stable form of carbon at the pressures and temperatures that reign in
the lower part the lithosphere. Given that carbon is relatively abundant in mantle
rocks, it is probable that this part of the mantle is a vast reservoir of the gemstone.
Kimberlite magma is merely a vehicle that transports the diamonds rapidly to the