Hardness test is Mohs scale, which is used in mineralogy. One tool to make this measurement is the sclerometer. Another tool used to make these tests is the pocket hardness tester. This tool consists of a scale arm with graduated markings attached to a four-wheeled carriage. A scratch tool with a sharp rim is mounted at a predetermined angle to the testing surface. In order to use it a weight of known mass is added to the scale arm at one of the graduated markings, the tool is then drawn across the test surface. The use of the weight and markings
71 Harrington Street, The Rocks and working classes in residence in The Rocks between the 1890s and the mid 1970s. The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales. The retained section of the house has aesthetic significance as part of a strong visual precinct forming a characteristic Rocks townscape with the adjacent terraces and the Harbour Rocks Hotel on the other side of the street. The retained street section of the former house enhances the human scale of the streetscape and reinforces the historic character of The Rocks. The item meets this