Cage
It is the elevator which is used for moving people up and down the mine shafts.

Calcination
It is the process to roast metallic concentrates in order to remove sulphur prior to smelting.

Calcite
It is a very common rock forming mineral which comprises of calcium, carbon and oxygen (CaCO₃).

Calcite group
It is a group of minerals that belong to the carbonate group and are isomorphous with one another, having the same properties. This groups minerals may partially or fully replace one another. For example, iron can take the place of magnesium in Magnesite (MgCO₃), transforming to Siderite (FeCO₃).

Cambrian
It is a period of geological time which is 545 to 495 millions ago. It marks the begining of the Paleozic Era.

Cannel coal
Sapropelic coal type.

Carbonate
It is a mineral that is characterised by a fundamental structure of CO3. The common examples are calcite, dolomite, magnesite and siderite.

Carbonatite
It is a magmatic rock which consists of calcium carbonate and is usually associated with nepheline-syenite systems.

Carboniferous
It is a period of geological time which is 354 to 292 million years ago. It is named such because of the globally extensive occurrence of coal and limestone (CaCO₃) during this time. In the United Kingdom, the Lower Carboniferous is dominated by the marine sediments and the Upper Carboniferous rocks are almost entirely fresh-water and lacustrine sediments. The bulk of the coal deposits in the United Kingdom occur in the Upper Carboniferous strata.

Cat's eye
It is a mineral having dense inclusions of tiny, parallel, slender, fibers which can cause it to exhibit chatoyancy. The most notable is Chryssoberyl Cat's Eye, or simply known as Cat's Eye.

Cavity
It is the hollow area in a rock which develops due to some form of stress. Many cavities are lined with crystals.

Cementation zone
It is an underground area where certain elements are concentrated which may combine to form some new, or primary minerals.

Cenozoic Era
It is a period of geological time which is extended from 65 million years ago to the present.

Chatoyancy
It is a Phenomenon of certain cat's eye minerals that causes it to exhibit a concentrated narrow band of reflected light right across the center of the mineral. It is generally seen on polished cabochons only.

Chert
It is sedimentary rock which is ultra-fine grained and is composed almost entirely of silica. It can be of organic or inorganic origin.

Chromates group
It is a group of minerals which are the compounds of one or more metallic elements being combined with the chromate radical (CrO₄). This groups minerals are generally heavy and brightly colored. Chromates are rare and are usually classified as a sub-group of the sulfates.

Claim
It is the mining right granting the holder the exclusive right to search, within a specific given territory, for any mineral substance. It may exclude peat, sand, clay, gravel, hydrocarbons, brine and stone used for the industrial purposes.

Clast
It is the fragment of either rocks or the minerals which is broken off from a large piece.

Clay
It is a mixture of very grains of the micaceous substances. When wet, it is plastic and hardens when heated. It mainly consists of hydrous aluminum silicates.

Cleavage
It is a term used for the splitting or tendency of a crystal to split along the definite crystalline planes to produce smooth surface.

Coal
It is a black or brownish-black solid combustible substance, which are formed by the partial decomposition of vegetable matter and it is widely used as a natural fuel.

Coating
It is a thin layer of one mineral on the surface of another.

Coking coal
It is a term for the trade category of coal which is used in the steel industry to de-oxidise iron ore in the blast furnace.

Columnar
It is an aggregate which describes a mineral having parallel, slender, adjoining crystals.

Concentrate
It is a substance of value which is produced by physical and/or chemical processing of ore.

Conchoidal
It is a fracture in a mineral where the indentation resembles a shell.

Contact metamorphism
It is a process of mineral or rock metamorphism that is caused from the magma intrusion near the contact with the magma.

Contact twinning
It is a form of twinning in which two crystals join together at a base. Few examples are, japanese twin, spinel twin, and chrysoberyl twin.

Containment pond
It is the structure for the accumulation of solid, chemical or dangerous substances to prevent their dispersal into the environment.

Contaminant
It is any element or natural substance, the concentration of whose locally exceeds the background concentration, or any substance which do not occur naturally in the environment.

Core sample
It is the cylindrical sample of rock which is taken from the ground by drilling. It is used for research and exploration purposes.

Coxcomb
It is an aggregate which is composed of flaky or tabular crystals and looks like being adjoined from a base, with grooves between long, slender, arc-like crystals. Example: Barite.

Conchoidal
It is a fracture in a mineral where the indentation resembles a shell.

Cretaceous
It is the period of geological time which is from 142 to 65.5 million years ago. It marks the end of the Mesozoic Era.

Cross-cut
It is a drift in an underground mine which provides access to the orebody.

Crown or surface pillar
It is a body of rock of variable geometry which either contain or do not, minerals. It is located above the underground operations and it supports the surface above stopes.

Crust
It is a type of aggregate, but disorganized, crusty, mineral coating which can be thin or thick.

Crystal
It is a term given to any particular three dimensional form which a mineral exhibits. It is classified by the distance ratio and angle of constituent parts.