type of art made from tiny pieces of stone

Like these:

http://www.google.com/images?q=mosaic&hl=en&rlz=1C1GGGE_enUS379US379&prmd=ivnsm&source=lnms&tbs=isch:1&ei=I8FmTcOuH4Gclge9lOWCAg&sa=X&oi=mode_link&ct=mode&cd=2&ved=0CB0Q_AUoAQ&biw=1366&bih=643