The Beauty of Chemicals

Many pure substances in the laboratory are either dull, white powders or dull, coloured powders. If they are dissolved and allowed to crystallize slowly, their geometry becomes apparent to the naked eye, and light interacts with crystals far more elaborately. In nature's laboratory, impurities, heat, and pressure help convert compounds and elements into minerals. These new forms retain their basic ratios of bonded atoms, but as the philosopher Santayana would say, minerals now objectify pleasure---in other words, they become beautiful.
Here are a few examples:
Mineral Main Chemical Compound

Pic from
Marcasite FeS2

Pic from Wikipedia.
Bornite Cu5FeS4

Pic from
Calcite CaCO3

Pic from
Realgar AsS

Pic from author.
Amethyst SiO2

Pic from
Sulfur S

Pic from author.
(not really a mineral but I formed this common organic compound by slow crystallization)