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
95-99 George Street, The Rocks aesthetically significant for containing some of the most intact Victorian period interiors for shops and residences in The Rocks area, including internal linings, joinery, some door and window furniture and an original plan form. 95-99 George Street makes an important contribution to the streetscape of George St, and is of significance in continuing the uniform character of the small scale retail shop buildings found in The Rocks. The building is aesthetically significant for its contribution to the streetscape of Greenway Lane, one of the pedestrian laneways in The Rocks area which are highly significant as evocation of the colonial townscape.