Candelabrum — Lampstand, decorative motif of similar form in mosaic.
CARTELLINO — A piece of mosaic paper, about 5 x 7 cm, which is stuck to the back of a mosaic sheet and is visible from the front, the section numbers, therefore, can be verified after the tesserae is pasted.
CARTOON — Full-scale drawing, complete with chiaroscuro, upon which the mosaic is based; it is used together with a full colour bozzetto.
CASTING FRAME — In mosaic context, a wooden frame that is used to cast concrete slabs for the indirect mosaic method.
CEMENT — A hydraulic binder produced by burning a mixture of limestone and clay in rotary kilns. The resulting product, called clinker, is then ground and mixed with small amount of gypsum plaster. It hardens by hydration when water is added. The resulting mortar is considered hard after 28 days. However, the hardening process continues for several years.
CEMENT MIXER — Tool used for mixing lime and concrete.
CERAMICS — Ceramics are produced by baking clay. Generally, ceramic materials fall into two main categories: porous, absorbent ones (terracotta, majolica, earthenware) and compact, impermeable ones (stoneware, single-fired ceramics, chinaware).
Chinoiserie — A style reflecting the fanciful perceptions of Chinese life and art held by the Europeans from the 17th century onwards.
Chip mosaic — Mosaic formed of irregular chippings of stone.
CLASSIC TECHNIQUE — Mosaic technique developed during the Classical period, that is, between the fall of the last Athenian tyrant in 510 BC and the death of Alexander the Great in 323 BC.
CLAY — Clay is an aluminium silicate which also contains other silicates, iron oxides, alkali, calcium sulphates and organic substances. It contains a certain quantity of water and, immediately after extraction, it has a plastic consistency. If properly modelled, clay dries and hardens preserving its natural colour.
Cobalt — A metal, the oxide of which produces a strong blue and a stable ceramic pigment that can be used at a wide range of different temperatures; used in the decoration of tin-glazed tiles and later printed blue-and-white tiles.
COCCIOPESTO — An inert material that is mixed with lime to produce a red-coloured material. Pounded cocciopesto can be used to make ceramic floors, sometimes decorated with tesserae (opus signinum).
COGOLO — Partially calcined limestone, a leftover of lime production. When a limestone rock is not completely calcined, it becomes white and is used as a cutting stone to cut mosaic tesserae or marble chips for Venetian terrazzo floors. There are two types of cogolo: the "male", compact and very smooth; the "female", which has a granular and less compact surface.
CONCRETE TOPPING — Mixture of sand, cement and water installed on a pre-existing floor. Once dried, it is used as a backing for tiles and mosaic floors.
COPERTA — A mixture of lime and ground terracotta that is spread onto the loose stone foundation of terrazzo floors, can be of different thicknesses. The setting bed is spread onto this layer.
COPPO — A curved roof tile made of clay.
COSMATI WORK — Type of mosaic technique derived from opus sectile and named after a family of marble workers — the Cosmati — active during the 12th and 13th centuries. Cosmati work is characterized by right-angled, square and triangular tesserae forming geometric patterns around roundels of red porphyry and green serpentine.
Crenellation — Also known as a battlement, a pattern of multiple openings along the top of a defensive wall, through which arrows or other weapons can be shot, used especially in medieval architecture. Motif imitating the crenellations is frequently used in the borders of mosaic pavements.
Cuenca — Spanish for 'bowl'. Another term for ARISTA.
Cuerda seca — Spanish for 'dry cord'. A decorative process where the design is first painted in outlines using a compound of iron or manganese oxide and grease. Colours are then added but these do not cross the greasy lines. After firing, these outlines appear as matt dark sunken lines separating areas of glossy colour. The earliest form of the technique involved the use of a thin cord, impregnated with the iron/manganese and grease mixture which was carefully placed on the surface of the tile to create the outlines of the design.
CURING — The process of drying out cement and cementitious adhesives.
