Bismuth is a metal you can melt on your stove top, as it dries it forms these beautiful crystals. My father bought me some of the raw metal for Christmas several years back. Perfect for the science oriented home experimenter!
Why do humans tend to prefer strict geometric design when nature seems to flow in a chaotic and organic way? "Fractal Experience" Visual Arts, Illustration, Photo Manipulation by Erik Söderberg (Uppsala, Sweden).
The range of colours shown by fluorite is equaled by few other gemstones. It may occur in beautiful cubic crystals or as a massive crystalline variety displaying banded or radiating patterns. Although the stone is somewhat soft for use as a normal.