These agate stone beads were found in the vintage bead hoard! We aren't exactly sure what the stone is, but we know its a type of agate. They are 20mm x 3mm thick. They are drilled on the slant so that they lay nicely on the string in a diagonal sort of fashion. These beads are strung on a 30 inch long strand with approximately 42 beads. It's a great deal for this amount of beads.