Amethyst is a variety of macrocrystalline Quartz (SiO2) displaying shades of violet due to the presence of small amounts of Fe3+ ions. The colour is usually strongest in the crystal terminations. It is a popular semi-precious gemstone. However the colour can fade in strong light. Interestingly heating can give rise to green, yellow and brown tones.

Description: This is an interesting specimen because it consists of two layers of deep violet amethyst sandwiched between two layers of white quartz. The amethyst is very lustrous and good crystal terminations can be observed on the outside faces.

Location: Friesenberg, Namibia.