What did you put behind the fabric to make it shine?
After much consideration I decided I wanted an almost mirror finish behind the heart. Silver fabric was pretty but not shiny enough, and actual mirror was too thick and heavy, so I went with shiny silver paper. The silver paper isn't acid free (which is not ideal) but I couldn't find an acid free version I liked as much.
I figure my stitching will all go to the Goodwill when I'm dead (no one in the family has a love for it), so longevity isn't a huge concern for me. Paper that has acid in it can last for 20-50 years if kept dry and out of the sun, before it starts to desintegrate and damage your fabric. That's long enough for me.
FYI: They have this shiny paper in both silver and gold colors in the framing department of Hobby Lobby...it's in the slots right next to the mounting boards.