These are 13-Piece mini-collars or fans, in a wide variety of semi-precious gemstones. All fan sets have finished (rounded) edges on the lower front of each piece, unless otherwise noted.
Exact sizes are not quoted for these fans because they vary in size - both from gemstone to gemstone and from shipment to shipment. In general, The smallest (outer) pieces are about 10mm long and the largest pieces (center) are about 25mm (for most jaspers, agates, quartz, aventurines, and howlites). Items like Mother of Pearl will be smaller than those measurements - and items like hematite will be bigger.
You will find these collars called by many different names, such as "spikes", "Egyptian Fans", or "stick beads". The 'mini' term is usually used for fans that have 13 pieces. We do not carry the larger sets (39 or 41 pieces) due to the difficulty of getting them on a regular basis.