My enchanter (Tunare worshipper) made this earring today using topaz imbued by a cleric worshipping Quellious. With a jewelry skill of 157, the success rate was one for three, and this item was not trivial, although the electrum version was...leading me to believe that imbued gems follow the same triviality levels as regular gems.
My experience with making silver items from imbued gems is that the trivial levels are indeed the same as for normal items.
However, given the recipies and teh bizzare stats that are produced from various imbued gems, there seems to be little incentive for making most of them!