This is a project I've been working on for some time. I am trying to get it ready for Valentine's day 2015. Basically, it was a flat piece of carbon fiber that I had die-cut into a heart shape with an inverted heart shape cut out of the middle. The next step in the process was bending the whole shape right down the middle at a 90˚ angle, so that it would lie flat on a horizontal surface.
The bending of the shape and the size of the inverted heart was problematic. I tried bending it over a coat hanger, softening it in a low heat oven, taking a heat gun to it, etc. I have finally found a solution that seems to work pretty well.
I have an old flat clothes iron that heats slowly and uniformly ( important ). I take the heart shape and hold it on the edge of the iron until it gets soft enough to bend, and Voila ! I have my rock holder.