Blackstone is another term used for Black Jasper. It is part of the Chalcedony family and made of silicon dioxide. This measures 7 on the Moh's scale, which means that it is very hard.
Going back many thousand years, Blackstone has been used to assay for gold content. Rubbing the alloys on the stone, called a touchstone, produces a streak the colour of which determines the gold content within 1 part in 100.There are references to the touchstone by Greek Poet Theognis in 6th century BC and in ancient India in the Arthshastra.
This gemstone is believed to be highly protective and bring good luck to the wearer in a fight - whatever the type, legal, political or even mental.
Jewellery that uses Blackstone