Jet refers to a fossilized coal which is also known as agate. It is hard and light weight and is a lustrous black color.. It was used in mourning jewelry during the Victorian period. B lack glass and plastics are often made to look like jet. True jet is warm to the touch.
Jet jewelry has been made and worn for centuries, but it became more popular after Queen Victoria wore it to mourn the death of Albert. After this, it was considered widely in Great Britain as an approriate jewelry to wear at funerals