Pietersite is a variety of chalcedony that is known for its swirling hues of various colors. Often, it will contain a bouquet of browns, reds, greens, blues, and golds. The stone also features a light chatoyancy. It is sometimes compared to tiger's eye, and this is not unreasonable.
Pietersite is sometimes called the "Tempest Stone," "Arizona's Tiger Eye," or "Eagle's Eye." The stone is typically cut for lapidary projects. As a variety of chalcedony, it has a 6.5–7 hardness on the Mohs scale.
Metaphysical Properties of Pietersite
Pietersite is a gorgeous stone that holds the power of the Essential Storm of the Universe. Pietersite is also known as Tempest Stone, and it imbues us with the integrity, honor, and wisdom that we need to sail through the storm. Pietersite stimulates your drive toward enlightenment and works as a conduit of supernatural power between you and the Astral Realm. Pietersite encourages the power of your Third Eye and helps you strengthen your intuitive abilities, particularly when it comes to uncovering the truth. Through meditation with Pietersite, you have access to the Akashic Records and can understand higher principles of mysticism. Pietersite is a powerful stone for purging negativity, creating a calm and balanced radius around you, like the eye of a storm.
Large Pietersite specimens often feature a beautiful mixture of brown, red, green, blue, and gold. Smaller specimens tend to exhibit two or three of these colors, due to their size. Pietersite is a form of Chalcedony with Amphibole mineral fibers embedded within it. This can cause a shine in some specimens that is similar to Tiger Eye, and indeed it is sometimes sold under the trade name “Arizona Tiger Eye” though the two stones are not related.
Sources
https://www.mindat.org/min-960.html
https://www.mindat.org/min-27262.html