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
105 George Street, The Rocks at 105 George Street, 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. 105 George Street is a reconstructed, typical example of a simple 19th century shop and residence. The building has been used for commercial purposes for more than 150 years. The building makes an important contribution to the surrounding 19th century commercial precinct and contributes to the character of the surrounding area of The Rocks. 105 George Street,