I also submitted several other topics and the rest is history. Although I am chemically literate, I'm not a research chemist. On the other hand, my audiences typically have little acquaintance with earth and planetary science. I view my role as providing some hopefully entertaining and interesting ideas that cross the borders of both disciplines. In the past two decades spectacular progress has been made in understanding why minerals and materials in general display the colors they do.
Ionic crystals owe their colors to crystal-field mechanisms.
Metals and semiconductors owe their colors to the existence of energy bands. In a semiconductor, there is an energy gap between the energy levels of the valence electrons and the energy levels that can be occupied by free electrons. There is a vast industry in the United States that is engaged in the manufacture and dissemination of scientific misinformation . Pseudoscience, or ideas that claim scientific validity but are demonstrably faulty finds an audience for a variety of reasons . Virtually all pseudoscientific theories have elements of the anti-authoritarianism that fueled the Laetrile campaign of the 1970's.