6 Dramatic Long Agate Barrel Beads - Heavy!Agate is for mental energy and study. Price is for 14 inch string of these striking beads 6 to the string each measure a long 57mm x 14mm. What is agate? Agate is nature's most striped gemstone. A variety of micro crystalline quartz that forms in layers and many colours and texture, by filling a cavity in a host rock although it is usually in round nodules with bands looking like eyes in the rings of a tree trunk. Different colours are caused by iron