Mohs scale of mineral hardness integrity, they are not considered "scratches" for the determination of a Mohs scale number. The Mohs scale is a purely ordinal scale. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is four times as hard as corundum. The table below shows the comparison with the absolute hardness measured by a sclerometer, with pictorial examples. On the Mohs scale, a streak plate (unglazed porcelain) has a hardness of approximately 7.0. Using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale. The table below
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