Mineral necessarily constant for all sides, which is a function of its structure; crystallographic weakness renders some directions softer than others. An example of this property exists in kyanite, which has a Mohs hardness of 5½ parallel to [001] but 7 parallel to [100]. The most common scale of measurement is the ordinal Mohs hardness scale. Defined by ten indicators, a mineral with a higher index scratches those below it. The scale ranges from talc, a phyllosilicate, to diamond, a carbon polymorph that is the hardest natural material. The scale is provided below: Lustre indicates how light reflects from the mineral's
Mineral Revolution and formed the basis of the apartheid system, which dominated South African society for a century. The Mineral Revolution began with the discovery of diamonds at the town of Kimberley in 1867. The discovery of diamonds led to a rush of prospectors descending on the town, whose population skyrocketed as increasing numbers of prospectors arrived to seek their fortune. As more diggers arrived in Kimberley, diamond-mining increased in scale, focusing in open-pit mining of three main sites. As surface deposits of diamonds were excavated, deeper pits had to be dug, propelling the Mineral Revolution into a new phase. To excavate