A very effective diamond-tipped bow drill construction by indigenous technology is being used by the Cambay lapidary in India to perforate tough and hard silica beads. Construction of the bow drill consists of: 1) the bow made from a long bamboo stick and thick string and 2) the arrow consisting of a wooden rod. The use of single and double bit drillers is discussed. Each bead is perforated from both the ends so as to meet at the center. Silica powder, a precious by-product of this drilling method is used for bead polishing, and is the main reason why Cambay lapidaries use the bow drilling technique instead of more modern techniques.