Our Small Diamond Core Drills allow good circulation of water and will stay cooler whilst drilling. The Small Diamond Drill Bits have a solid end and therefore a wider surface area. Both can be used for drilling holes in Pebbles. If you're a beginner and have a Dremel Rotary tool then you might like to start off with our Diamond Drill Bits Set for your Dremel Tool. This includes a mixture of small diamond drill bits and core drills and a Dremel Multi Chuck which you will need for holding these small bits in your Dremel Rotary Tool.