The present subject matter relates to an indexing unit for a gemstone processing machine. The indexing unit may include a base plate that may comprise a plurality of plates. Further, the base plate may be coupled to an indexing mechanism such that the indexing mechanism may impart rotational, translational, and tilting motion to the base plate. Further, the plurality of plates may include axially extending concentric holes in which a plurality of holders may be disposed. Further, the plurality of holes may hold the gemstone for processing. In one implementation, the plurality of holders may be coupled to one or more actuating mechanisms that may impart rotational, translational, and tilting motion to the individual holders.