Black Tigers Eye from South Africa
The colour of black tigers eye is produced by heating the brown and yellow coloured stone. Heat changes the chemical composition hence initiates a change in colour.
Heat treatments are widely used to enhance or change the colour of many rocks and minerals. This practice which has been in use for thousands of years was first documented by ancient Greek philosopher Theophrastus.
Unlike the red variety of tigers eye which is also heated, the black stone retains its chatoyant properties.
Chatoyance is an optical phenomenon seen in certain minerals. It's caused as light reflects off the fibrous structure, inclusions or cavities within the stone.
As a chatoyant stone reflects light a narrow band of reflected light can be seen. As the angle of light changes the band of light moves which can give the impression colour and markings are moving. The quality of chatoyance varies from one stone to the next.
These fine grade black tigers eye crystals are wonderfully tactile. No two pieces are the same. Although classed as a medium sized stone size can vary from piece to piece. We also have black tigers eye crystals in extra large sizes.
