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
71 Harrington Street, The Rocks Iron. As at 27 April 2001, Archaeology Assessment Condition: Partly disturbed. Assessment Basis: Area under building only. Terraced into hill slope. As at 30 March 2011, this house 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. The site has historical significance as part of the Colony's hospital site in 1807, and the building as part of the 19th century housing stock in The Rocks. It has aesthetic