Mohs scale of mineral hardness finding the hardest material that the given material can scratch, or the softest material that can scratch the given material. For example, if some material is scratched by apatite but not by fluorite, its hardness on the Mohs scale would fall between 4 and 5. "Scratching" a material for the purposes of the Mohs scale means creating non-elastic dislocations visible to the naked eye. Frequently, materials that are lower on the Mohs scale can create microscopic, non-elastic dislocations on materials that have a higher Mohs number. While these microscopic dislocations are permanent and sometimes detrimental to the harder material's structural
Lilyvale, The Rocks majority of external render was removed and the brick walls painted. As at 30 March 2011, "Lilyvale" and site are of State heritage significance for their historical and scientific cultural values. The site and building are also of State heritage significance for their contribution to The Rocks area which is of State Heritage significance in its own right. "Lilyvale" Cottage is a very fine and rare example of Colonial Regency freestanding domestic architecture in the city centre. It is in good condition, having been conserved in 1987 by SCRA, and retains much of its early form and materials. The cottage