Beware of cheaper imitations often sold as 'Jet'. Ebonite or vulcanite, bakelite, black glass, coal, epoxy resins and other materials have all been used to imitate Jet. Most of these do not leave a brown streak when rubbed on a piece of unglazed porcelain though ebonite or vulcanite will. The definitive test is to use a red hot needle on some inconspicuous part of the item when a coal-burning smell will ensue. However be very careful not to destroy or damage the item, remember Jet will burn. A safer way is to closely examine the item in question - signs of moulding (rounded edges rather than the sharp edges obtained by carving) or fading in sunlight to a khaki colour are sure signs that the item is an imitation. Remember also that Jet is warm to the touch unlike glass for instance. .
Jet can be safely washed in a mild detergent and warm water. It is recommended that moistened cotton wool swabs be used to gently remove any surface dirt. The Jet should then be allowed to dry and then the ‘shine’ can be restored by gently wiping with baby oil. Always keep Jet separate from other jewellery since it is relatively soft and can easily be scratched. It is suggested that each piece should be wrapped in tissue paper to prevent rubbing against other items.