Tumbling Lapis

Can someone here give me some tips on polish/tumbling lapis. I have a few pieces of lower grade stuff and some of the darker pieces came out horribly. The piece at the very top is fairly "shiny" but most have a satin-type finish to them. Unfortunately, my two favorite darker pieces, have a rough feel to them. I do think part of my problem is that I polished them with harder stones. Can I re-tumble them with...let's say marbles? If I can re-tumble them at what grit stage should I start?

Many thanks,

Henry
San Francisco Bay Area

I would say your major problem is tumbling the Lapis with harder stones after the first grit. When I tumbled I always added harder stones with the first grit( being from Maine we are frugal and it saved spending money on grit). After the first grit I culled out the harder stone. So I think if you returned to the second grit and start out again you should be able to produce some nice but smaller tumbled Lapis. Also consider what you add when polishing - I used various items like plastic pellets to the polish.
Let us know how your project turns out.
Tom