Water Sapphire (Iolite)

The stones are amazing . Just wondering if I need to tumble them to get the brilliant blue effect of the sapphires . After doing the ring I thought the sapphires would pop more but did not and maybe that is because I did not use the diamond dust . Ring cores are of beautiful quality. Love the tungsten and silver cores no need to look else where.

17 year old ring maker. Very nice to work with.
The ones I got didn't turn out blue, and ended up having a shade of black.
Didn't ruin my ring, and it still came out perfect.
Already used the gemstone twice so far.
If you have any advice on working with this gemstone that would be nice.

This stone is beautiful and works well with many designs