On eof the confusing things for new people into glass jewels is figuring out sizes. Most glass jewels come in millimeter sizes..Alost any ruler you look at will have this measurement opposite the inch measurement. 25mm is approximately 1 inch.. Some rhinestones are sized a lot smaller by SS or PP measurment.. SS is approximately alittle over 1/4 of MM sizes. For example: SS17= 4mm SS22= 5mm SS28=6mm SS33=7mm SS38=8mm SS42=9mm Smaller sizes now are called pearl plate: PP2=1mm PP13=2mm PP23= 3mm Slight increases from 1-2-3mm would be reflected in the PP sizes PP3 PP4 PP5 etc..