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Technical Terms
alluvial diamonds: diamonds found in river sediments.
bedrock: the solid rock under deposits of gravels, sands, soil and silt.
breccia: a coarse-grained clastic rock composed of angular fragments.
carat: a unit of weight for gemstones that formerly varied from country to country but is now standardized as a metric carat of 200 milligrams or 0.20 of a gram.
concentrate: dense minerals concentrated together during an extraction process while the rest of the material is rejected.
cut and fill method: a method whereby rectangular areas of ground are stripped of overburden, the diamondiferous gravels removed for processing, the processed gravel and overburden replaced and the ground rehabilitated in one continuing cycle.
deposit: a coherent geological body such as a mineralized body.
diamondiferous: containing diamonds.
electromagnetic survey (or EM survey): a survey of the conductive properties of rocks.
grade: (to contain a particular) quantity of ore or mineral relative to other constituents, in a specified quantity of rock.
karoo: a tablesand found especially in southern Africa that commonly rises to a considerable height in terraces. It does not support vegetation in the dry season but becomes a grassy plain or pastureland during the wet season.
kimberlite: an igneous rock of mantle origin occurring in intrusive breccia pipes, which is sometimes diamond bearing.
mantle: the ultramafic layer of the earth beneath the crust.
mineral resource: in-situ mineral occurrence from which valuable or useful minerals may be recovered.
overburden: material that overlies bedrock.
pipe: a roughly funnel-shaped, approximately vertical extrusion of volcanic breccia and kimberlite that may or may not contain diamonds.
prospect: mineral occurrence with the potential for an economic deposit.
quality: the degree of excellence of a diamond, measured by its weight, colour, purity or clarity and its perfection of proportions and finish.
sediment: unconsolidated material, both mineral and organic, that has come to rest on, or is being transported over, the earth's surface by water, wind or ice.
terrace: an alluvial deposit on a flat area of a river or former riverbank. Also known as a bench placer.
ultramafic: igneous rocks of mantle origin with low silica contents.
volcanic: descriptive of rocks originating from volcanic activity.
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