Onyx is a bicoloured, fibrous variety of chalcedony, which in turn is a variety of the mineral quartz. Agate is a similar, but multi-colored variety.
NOTE
Do not forget that every stone needs care. This can vary from stone to stone. However, as a rule of thumb, whenever possible, clean your stone under running water, especially if different people are massaged with the same stone!
The gemstone ball has a diameter of about 3.0 cm and fits in all Joya massage products.
