Mohs scale of mineral hardness Mohs scale of mineral hardness The Mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. Created in 1812 by German geologist and mineralogist Friedrich Mohs, it is one of several definitions of hardness in materials science, some of which are more quantitative. The method of comparing hardness by seeing which minerals can visibly scratch others is, however, of great antiquity, having been mentioned by Theophrastus in his treatise "On Stones", c. 300 BC, followed by Pliny the Elder in his "Naturalis Historia", c.
Our Lady of the Rocks long journey, and eventually, she became blind. She used golden and silver fibres but what makes this tapestry so famous is the fact that she also embroidered her own hair in it. Our Lady of the Rocks Our Lady of the Rocks (, ) is one of the two islets off the coast of Perast in Bay of Kotor, Montenegro (the other being Sveti Đorđe Island). It is an artificial island created by bulwark of rocks and by sinking old and seized ships loaded with rocks. The Roman Catholic Church of Our Lady of the Rocks () is the largest