Engraving is an entire process and even includes fundamentals and guidelines from this site
that need to be followed in order to achieve good quality work.
Diamond-drag Engraving - Also known as 'scratch', diamond-drag engraving uses a non-rotative tool that has a cone-shaped diamond tip, that is used by dragging it with added pressure through metal.
Burnishing - This method makes use of a rotatory tool with a limited amount of pressure. It can either be a diamond cutter, carbide or have a varying tip width.
Rotatory Engraving - Using single/ multiple fluted tools for cutting. This tool rotates through your work in order to remove material, leaving the result as an exposed core of the material.