Seikos use a hardened kind of glass for their crystals and takes some time to polish, be advise. I had good results using 400,600.1000 and 2000 grit wet type sanding paper and finishing with cerium oxide, this powder is use for the purpose of polishing glass and acts chemically and abrasibaly over the glass.
the key is to change to the next sanding paper untill you remove the scratches from the previous completely, use plenty of water, I use soapy water and do the sanding over a flat surface, I use a granite tile for this. when you are done with 2000 grit it will be shiny with no pits or scratches, the cerium oxide polish will take care of the rest in no time if the sanding was done right. One piece of advise if you are married, stay out ot the kitchen.