The Vickers hardness
is measured using a standardised square-based diamond pyramid-shaped tip with an angle of 136° at the top between the sides.
Therefore, the indentation is square shaped. The more significant the indentation is, the more the indenter has gone into the material and the less hard the material is. The two diagonals d1 and d2 of this square are measured using an optical device. The value d is obtained by computing the average of d1 and d2. Such value d will be used for the calculation of the hardness. The strength and duration of the support are also standardised.