Weigh down the smaller bowl with coins/small weights. Paint the inside with a shiny paint. Copper was the reddish color in the picture.
have shapecrete already pressed down into a plastic lined bowl, level the top. Paint leaf and second bowl with oil and press down into the first bowl (maybe weight second bowl with water?) no instructions at click through but lots of ideas
DIY-Anleitung für Schmuckschalen aus Beton / diy tutorial: concrete bowls for…
egg holder made of concrete
22 Seriously Cool Cement Projects You Can Make At Home.I like the cement letters and fire bowls.most of the how-to on buzz feed w/links to more info