Crystals have been used in Vodun and the African diaspora for centuries, but few people alive today know exactly how they were used originally. There has been a lot of mixture of belief from Hinduism, Kemetic, and other systems, trial and error over the aeons, and so crystal use and therapies have become a bit universalized over time. The main difference though, is context. Different cultures are going to have different needs, and use crystals in different ways even though their energies are standard.
In my article, Crystals in African and Diaspora Mysticism, I try to give a small sampling of the use of crystals in the African context. One thing that needs to be mentioned is that many of the world’s minerals are mined in Africa, and not always under the best of circumstances. The circumstances under which a mineral was taken from the Earth is very important to us. We also believe that some minerals should be left in the ground unless they are needed for medicine. So returning such things to the Earth or choosing to use their energy from the Earth rather than digging them up, is a good deed.
Crystals and minerals are used in many ways, from house blessing to mojo bags. Archaeological digs have revealed various crystals that were purposefully buried in yards or with deceased African slaves in the Americas.