Rockwell scale for specialized applications. There are special scales for measuring case-hardened specimens. Rockwell scale The Rockwell scale is a hardness scale based on indentation hardness of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale (see below). When testing metals, indentation hardness correlates linearly with
Our Lady of the Rocks long journey, and eventually, she became blind. She used golden and silver fibres but what makes this tapestry so famous is the fact that she also embroidered her own hair in it. Our Lady of the Rocks Our Lady of the Rocks (, ) is one of the two islets off the coast of Perast in Bay of Kotor, Montenegro (the other being Sveti Đorđe Island). It is an artificial island created by bulwark of rocks and by sinking old and seized ships loaded with rocks. The Roman Catholic Church of Our Lady of the Rocks () is the largest