Alluvial Deposit
A concentration of gem materials created when rivers and streams transport sediment some distance from a primary deposit or another secondary deposit and redeposit it.

Alteration
Chemical changes in minerals occurring after a mineral is formed: typical of the reaction between mineralizing fluids and host rocks, and of the surface weathering of rocks.

Anomaly
Any departure from the norm which may indicate the presence of mineralization in the underlying bedrock.

Assay
A chemical test performed on a sample of ores or minerals to determine the amount of valuable metals contained.

Assessment Work
The amount of work specified by mining law that must be performed each year in order to retain legal control of mining claims.

Base Metal
Any non-precious metal (e.g. copper, lead, zinc, nickel)

Bottom Cut-off Screen Size
The size of the screen used to separate the product to be treated for diamond recovery from undersize material.

Bottom End
A general term used to describe the poorer quality and lower value goods in a parcel of diamonds.

Breccia
A rock in which angular fragments are surrounded by a mass of finer-grained material. Breccias may form by explosive volcanic action, by structural deformation (a “fault breccia”), by intrusive action (where the intrusive rock incorporates fragments of country rock), or by hydrothermal processes (where wall rock fragments are incorporated by vein material).

Bulk Sample
A large sample of mineralized rock, frequently hundreds of tonnes, selected in such a manner as to be representative of the potential orebody being sampled.

Carat
The standard unit of mass used for diamonds and other precious stones, equal to 0.2 gram. (The karat is a unit of concentration.)

Claim
A portion of land held either by a prospector or a mining company. In Canada, the common size is 1,320 ft. (about 400m) square, or 40 acres (about 16 ha).

Cleave
To split a rough diamond along the grain, usually using a metal knife in a kerf to divide the stone in two.

Core
The long cylindrical piece of rock, about an inch in diameter, brought to surface by diamond drilling.

Deposit
A body of rock containing valuable minerals; usage generally restricted to zones of mineralization whose size has been wholly or partly determined through sampling.

EM Survey
A geophysical survey method which measures the electromagnetic properties of rocks.

Diamond Value
The estimated average value of the rough diamonds in the deposit expressed in terms of US$ or US$/carat at a stated bottom screen cut-off size.

Dilution
Impact on mined grade through the contamination of non-ore species entering the extracted rock.

Exploration
Prospecting, sampling, mapping, diamond drilling and other work involved in the search for ore.

Facies
Term used to distinguish part of parts of a single geological entity.

Fault
A break in the Earth’s crust caused by tectonic forces which have moved the rock on one side with respect to the other.

Feasibility Study
An economic study assessing whether a mineral deposit can be mined profitably, by estimating the capital and operating costs of a mine and the potential revenues from production.

Fluvial
Of or pertaining to rivers, produced by the action of rivers.

Geochemistry
The study of the chemical properties of rocks.

Geology
The science concerned with the study of the rocks which compose the Earth.

Geophysical Survey
A scientific method of prospecting that measures the physical properties of rock formations. Common properties investigated include magnetism, specific gravity, electrical conductivity and radioactivity.

Geophysics
The study of the physical properties of rocks and minerals.

Grade
The concentration of diamonds in the ore, or stream in the processing plant, typically measured in carats per one hundred tonnes, carats per tonne.

Igneous Rocks
Rocks formed by the solidification of molten material from far below the earth’s surface.

Inclusion
Crystal of diamond or other material enclosed in a diamond during growth.

Indicated Resource
A resource whose size and grade have been estimated from sampling at places spaced closely enough that its continuity can be reasonable assumed.

Induced Polarization
A method of ground geophysical surveying employing an electrical current to determine indications of mineralization.

Inferred Resource
A resource whose size and grade have been estimated mainly or wholly from limited sampling data, assuming that the mineralized body is continuous based on geological evidence.

In-situ
In its original place; i.e. in unblasted or unbroken rock.

Kimberlite
A porphyritic alkalic peridotite containing abundant phenocrysts of olivine and phlogopite in a fine grained groundmass of calcite and second generation olivine and phlogopite and with accessory ilmenite, serpentine, chlorite, magnetite and perovskite. The most common host rock of diamonds.

Lamprophyre
An igneous rock composed of dark minerals that occurs in dykes; sometimes contains diamonds.

Laterite
A residual soil, usually found in tropical countries, out of which the silica has been leached.

Logging
The process of recording geological observations of drill core either on paper or on computer disk.

Maccle
Contact-twinned diamond crystal in which the two crystals have grown together with a 1800 rotation in the orientation of their internal structure.

Macro-diamonds
Diamonds that cannot pass through 0.5 mm square mesh.

Magnetic Survey
A geophysical survey that measures the intensity of the Earth’s magnetic field.

Makeable
A rough stone that would be most efficiently polished as one whole stone.

Measured Resource
A resource whose size and grade have been estimated from sampling at places spaced closely enough that its continuity is essentially confirmed.

Micro-diamond
Recovered diamonds less than 0.5 mm.

Mineral
A naturally occurring homogeneous substance having definite physical properties and chemical composition and, if formed under favorable conditions, a definite crystal form.

Open Pit
Surface mining in which the ore is extracted from a pit. The geometry of the pit may vary with the characteristics of the ore body.

Outcrop
An exposure of rock or mineral deposit that can be seen on surface, that is, not covered by soil or water.

Placer Deposits
Aeolian, alluvial, fluvial, beach or marine.

Point
There are 100 points in a carat.

Primary Deposit
Kimberlite pipes, dykes, blows or fissures, lamproites.

Recovery
Final separation process of diamonds from non-diamonds in the concentrate.

Reserve
That part of a mineral resource that can be mined profitably

Resource
The calculated amount of material in a mineral deposit, classified as measured, indicated, or inferred, based on the density of drill hole information used.

Sawable
A rough diamond, usually an octahedron or irregular stone, whose shape dictates that the stone should most efficiently be sawn into two pieces before polishing.

Stone Size
Size of a stone measured as carats/stone.

Stripping
Mechanical removal of overburden.

Tailings
That portion of the ground ore from which valuable minerals have been extracted and is rejected or floated during concentration, changes in technology or economic circumstances can sometimes make the tailings economic to reprocess at a later date.

Yield
Refers to the weight of polished diamond resulting after manufacturing a rough diamond.

Zone
An area of distinct mineralization.