What specific grit numbers did you use for each step, and how long did you tumble in the final polish stage? Sometimes with harder stones like quartz, you need to run the polish cycle much longer. Also, how full was your barrel with filler media?
Hey, wasn't there a guide online that said to fill the barrel like two-thirds full for the best action? I vaguely remember reading that quartz needs an extra long polish run, like double the normal time, because it's so tough.