A ball-tipped probe is most often used to assess the flatness of a surface, also known as scanning. By using a ruby ball probe, you are harnessing each of the advantages of ruby as a material—sphericity, hardness, smoothness, and resistance. Scanning is used in order to identify any flaws that a material might have. A ruby ball probe is used to measure the individual imperfections that are found during the scanning process. By running the probe across the surface of interest, you can find and measure the size of any flaws that exist. Ensuring smoothness and perfect sphericity of the ball on your probe is pivotal to successful scanning. Ruby is the best choice for this purpose since it is reliably spherical and smooth, as well as difficult to damage.