Vickers hardness numbers (HV) are a measure of a material's hardness, determined by the indentation left by a diamond pyramid under a specific load. The test involves pressing a square-based diamond pyramid into the surface of the material and measuring the size of the indentation. The Vickers hardness number is calculated by dividing the load applied (in kilograms) by the surface area of the indentation. This method is versatile and can be used on a wide range of materials, including metals and ceramics. The Vickers hardness test is particularly useful because it provides consistent results across different materials and can be applied to thin sections or small samples.