Chemistry in Pictures: Synthetic stone

The shiny silicate minerals known as micas form crystalline flakes that are thin and incredibly flat. These qualities make micas useful for a wide range of things, including atomic force microscopy and cosmetics. In the latter case, mica flakes add shimmer and opacity. Although mica is abundant in nature, makeup makers often want tight control over the color—they also need to be sure their cosmetics are free from heavy metals. Pigment provider Kuncai makes synthetic mica for just those reasons. The chunk on display in this photo, taken at the personal care ingredient convention In-Cosmetics Global 2024, was chiseled off a much larger polycrystalline batch made at one of the company’s production plants.

Credit: Craig Bettenhausen/C&EN