Black Onyx is a variety of the quartz family that’s a banded deep grey colour in its natural form. It’s mined from a number of places around the world including Madagascar, India, Uruguay and the USA although most of the high quality black onyx used for jewellery comes from Brazil. To achieve the uniform jet back colour we are all familiar with the semi-precious gemstone is either heat treated or died. Black onyx is believed to help if you are trying to break a habit.