The Silmarills tortured Morgoth, and the Wolf too, as well as driving the Wolf into a maddened Silmarill-powered muder-rampage. It may simply have acted differently on Trolls.
But afaik the only time Trolls are mentioned in the First Age is in the Battle of Unnumbered Tears...so it's hard to say, BUT if they were around Morgoth in Angband, it would seem that the Silmarill's didn't turn them to stone. But remember, they were extremly powerful Jewels.
I like the Olog-hai comment.
