Certain minerals are present in the rocks from the upper mantle that occur with diamonds in kimberlite and lamproite pipes, as seen in close by cases of xenoliths and diamond inclusions. Some of these minerals, being opposing to weathering and denser than quartz sand, concentrate in channel bottoms. Because they occur in distant greater abundance than diamond, exploration geologists look for these "indicators" among the gravel of regions they suspect may host diamond-bearing pipes.
Indicator minerals for diamond include, in categorize of decreasing significance: garnet, chromite, ilmenite, clinopyroxene, olivine, and zircon. But the order of resolution in streams is zircon, ilmenite, chromite, garnet, chromian diopside, and olivine. Diamond itself is clearly a most important indicator.
<< Back | Next >>