The Science of Amethyst

     Amethyst is one of the most well-known crystals in the gemstone, spiritual, and scientific world. It gains its attraction mainly from the vibrant purples it portrays from trace impurities in the structure of the crystal. This is exciting because we are going to look at it purely from a scientific perspective for the first time ever in these blogs. The chemical composition of Amethyst is very important to its structure, the molecular formula is SiO₂ (Silicon Dioxide). In this structure formation, the Silicon is connected to four Oxygens in a tetrahedral shape. The bond angle between the Silicon and the Oxygen is approximately 109^◦. As these molecules align with each other under immense pressure and extremely high heat, they create layers forming a prismatic crystal that has pyramidal shapes on either pole.

     The formation of Amethyst is quite interesting in that it starts with the silica-rich fluids that circulate through the earth’s crust and are usually associated with hydrothermal vents or volcanic activity. This is where that intense heat comes in and is usually upwards of several hundred degrees Celsius. In the cavities of volcanic rocks, the fluids start to cool over time allowing the silica to precipitate into forming the prismatic crystals. Ferric Iron (Fe⁺³) and other trace impurities that were trapped in the silica-rich fluids then aligned themselves within the growing lattice of the quartz crystal. These impurities act as chromophores and accept specific wavelengths of light which allow our eyes to see what bounces back. Quick side note on that, for those who aren’t familiar with how our eyes perceive color. The colors we see are almost like “leftover wastes” of light that the objects we look at do not accept. Light has every color known to humans (and ones we cannot see with our eyes) and when that light enters an object, the object accepts all the wavelengths of light except the ones we see bouncing back to us. Long exposure to UV light can affect the Amethyst’s color expression, removing most of it or all of it altogether.

     Cleaning Amethyst that you may have found or is dirty can be a daunting task but, there are some easy and simple ways to take care of this. If you dug for Amethyst and it has clay stuck to it, scrubbing it with a toothbrush and warm, soapy water can take care of this. If it still has some clay in little pockets, an ultrasonic cleaner can remove any clay or other minerals attached to the crystals. Using low heat would be ideal because sudden changes in temperature, especially high heat, can cause small fractures in the crystals. These fractures coupled with the vibrations from the ultrasonic cleaner can cause the crystals to break apart.  So always have some caution when cleaning the crystals. If the ultrasonic cleaner doesn’t remove any iron staining or other smaller trace minerals attached to the Amethyst crystals, you can use Iron out or Muriatic acid to combat it. Dealing with any acid is dangerous so using a mask, gloves, and plastic containers is advised. Also make sure to have the set up outdoors and never breathe in any fumes, keep the set up away from children, and make sure you follow any instructions on the bottles of powder for both acids.