Structural Colouring The rainbow iridescence you see on this chocolate requires no additional pigments or ingredients. We create it using the same effect found in oyster shells and butterfly wings, known as structural (as opposed to chemical) coloration. It’s just chocolate! Galantamine Inside, however, we can add exciting ingredients beyond the usual sea salt or mint essence. One is the natural drug galantamine, an extract of the snowdrop flower, which is known to induce lucid dreams and at higher doses, to treat Alzheimers Disease.