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
121 George Street, The Rocks and has been continuously occupied for commercial and retail purposes since construction in 1880. The building's scale and alignment to the street is typical of that found along the west side of George street and lining the harbourside as part of the business precinct of The Rocks. The building is part of the rich fabric of The Rocks which is highly regarded by residents, Sydney people and visitors and acknowledged by the Australian Heritage Commission and the National Trust as part of The Rocks Urban Conservation Area. The building at 121 George street is expressive of the close weaving of