The metalwork in your pin appears to be repousse - a thin sheet of metal was pushed into a mold to create the stems and petals. I think the red flowers are coral, but it’s also possible that they are made of opaque glass, since the Czech Republic was known for its glass beads. Similarly, I think the green leaves are some form of form of jade or another natural stone, but they could also be a man-made opaque “stone.” A jeweler, or someone in a rock shop, could give you a more definitive answer.