Cement can be mixed with sand and used for installing indoor and outdoor mosaics. A mixture of sand and cement is often used for floor based mosaics where uneven tiles are required to make a level surface.
Cement is very alkaline and advisable to wear gloves and a face mask to prevent dust going into your lungs and burning your hands.
I recommend using a slow setting cement adhesive for interior mosaics as it gives you a longer working time and the ability to move pieces at the last minute.
DickBlick has a page dedicated to mosaic tile colorants and adhesives containing both adhesives and several different shades of colorant used to color the cement to match your mosaic.
MisterArt also supplies a formulated mosaic tile adhesive that is specifically intended for mosaic art use. This cement is available in several sizes from 4oz to 32oz.