If there is a sharp edge,on a stone-or even on a very few pearls- powerpro can cut through. A little reaming with a hand reamer will take the rough edge off, because the sharp edges are around the drill holes.
I have never used PP for gemstones though- I go with wire. We had one person reporting cutting through power pro by gemstones.
BTW Raison, the combo of one pearl, one gemstone, is a favorite with me. I did only that pattern in 2005 and it was extremely popular. It is beautiful and classic, that's why. I totally love pearls and pink quartz, but had great success with garnet pearl, garnet pearl too. I think I saw that in one of the strands on the cone thread....