These Black Crackled Agate beads are distinguished by the crackled pattern on their surface. The agate stone used to make these beads may be heated to accentuate the the unusual and beautiful design. Considered to be a variety of quartz, these agate beads are said to have a protective and energizing effect. If you look carefully you will see that no two beads are alike! Each bead measures approximately 4 x 4mm with a hole size of approximately 1mm. You will receive one strand measuring approximately 15" in length for each purchase. Multiple strands pictured. Each strand sold individually. Try these beads to add a unique touch your own designs!