Final answer:
The hardness of minerals is measured using the Mohs' scale, where minerals are ranked based on their ability to resist scratching by common objects with known hardness values. The Brinell hardness test mentioned in the question is a method to measure the resistance of materials to indentation, and is likely used by the engineer to understand material properties for different applications.
Step-by-step explanation:
The hardness of a material, specifically a mineral, can be determined using the Mohs' scale of mineral hardness. This scale, developed by Frederich Mohs, is a qualitative tool used for comparing the relative ability of minerals to resist scratching or abrasion. Each mineral is ranked on a scale from 1 to 10 with 10 being the hardest, like diamond, and 1 being the softest, such as talc. To determine the hardness of a mineral, one can use common objects whose hardness has been defined on the Mohs scale to perform a scratch test. For example, if a mineral can scratch glass, which has a Mohs hardness of about 5.5, then it must be harder than glass and would be placed higher on the scale.
When identifying minerals in rocks, geologists often use a hand lens to examine the minerals closely. Although minerals can be distinguished by their crystal structure and chemical composition, hardness remains a key characteristic for identification. The physical texture of a mineral, including whether it is coarse-grained or has interlocking crystals, can also provide insights into its identity.
In the case of the question, an engineer is measuring the Brinell hardness of different samples, likely to determine their suitability for various applications based on their resistance to deformation.