Mosaic pictures can be made from many different types of material. From the traditional smalti to coloured card cut into shapes. The different properties offered by these materials means that finished mosaics can be placed almost anywhere in the world, indoors or out. Below we list the most common materials used for making mosaics.

Tesserae is the collective name for the small tiles that when placed close together go to make up the mosaic picture.

Smalti

Smalti is the classic mosaic material. They are thick, rectangular pieces of opaque glass approximately 10x15x7mm. The glass is coloured with metallic oxides while molten. They are then allowed to cool into 'pancakes' approximately 31cm in diameter, from which the smalti is hand cut. This gives it its distinctly irregular surface with highly reflective powers. Smalti is normally sold in half kilo bags and by colour grouping. ie. golds, reds, yellows and oranges; whites, greens and blues; and blacks, greys and browns. Gold and silver smalti is made by placing silver or 24 carat gold leaf onto a glass backing and then covering with a thin layer of glass, often coloured. Again these slabs are hand-cut to various sizes but the common one is 20x20mm. Because the surface of smalti is pitted it is usually left ungrouted, so as not to dull the surface by filling in the holes with grout. The traditional method of pushing smalti into a bed of prepared mortar is partially self grouting anyway. As smalti has an uneven surface and pitted body it is not really suitable for floors, but is ideal on walls and small decorative pieces.

Vitreous Glass

Vitreous tiles are made from square glass of a uniform size and shape. The molten glass is poured into trays shaped like waffle irons and then pressed to give a flat upper surface. The reverse surface is bevelled and corrugated to give good adhesion. Because the edges are bevelled these tiles are ideal for use on three dimensional work as they allow the material to curve naturally. Vitreous glass offers the widest choice of colours. It is a lot cheaper than smalti and easier to cut. Virtually indestructable and frost proof it is an ideal medium for outside use. The flat upper surface makes it suitable for reverse working, ie. table tops and flat floors. The most commonly used size is 20x20mm and just under 1kg will cover approximately 30 sq.cm.

Ceramics

Ceramics encompass a wide range of materials that you can use. Available in a huge range of glazed and unglazed surfaces, ceramics represent what is possibly the most versatile of mediums. Kitchen and bathroom tiles are are available in many sizes and shapes and their colours range from soft pastels to full blown primary colours. Some are even made to represent stone and other natural finishes.Glazed tiles have a thin coat of colour on a white base, where as unglazed tiles have colour all the way through. This makes them very useful as they can be used however you want. Objects such as old vases, dinnerware and bowls offer another source of tile. By breaking them into random sizes or cutting by hand into specific shapes they can produce highly textured surfaces with interesting and sometimes humorous designs. It is not usually frost-proof, so is not always suitable for outdoors use.

Pebbles

Stone used to be the main material used for making mosaics, starting with the pebbles used by the Greeks thousands of of years ago. Pebbles are still used today but only by a few artists. As far as we know pebbles are not available commercially, but rely on the artist gathering a modest collection while walking along the beach or riverbank. The colour of the pebbles will depend on the geology of the area you are collecting them in. Mixed with other types of stone stunning mosaics can be made.

Marble

In the past many mosaics were made from marble and different local stones. Because of the varying tones and colours in a single sheet of marble it has a unique and varied interest. For years now marble has been used on floors, but it can also be used on walls. It is normally a thick material and one disadvantage of this is weight, which can make it tricky to fix securely in place. It is expensive but not as expensive as smalti, and can be obtained in a number of finishes. Marble can be polished to a glassy finish and in this way is generally supplied in small blocks known as cubes. Honed marble is polished, but stopped short of a glassy finish. This allows the colour of the stone to shine through but produces a matt surface, giving it a more natural appearance.