Olea capensis wood materials. It is also the one of the world's hardest woods according to the Janka hardness test. The timber has a good abrasion resistance and is very strong. It is an excellent turnery wood, and is used for a wide range of decorative items. Olea capensis Olea capensis, also known by the common name black ironwood, is an African tree species belonging to the Olive family (Oleaceae). It is widespread in Sub-Saharan Africa from the east in Somalia, Ethiopia and Sudan, south to the tip of South Africa, and west to Cameroon, Sierra Leone and the Islands of the
Vickers hardness test where "d" is the average length of the diagonal left by the indenter in millimeters. Hence, where "F" is in kgf and "d" is in millimeters. The corresponding units of HV are then kilograms-force per square millimeter (kgf/mm²). To calculate Vickers hardness number using SI units one needs to convert the force applied from newtons to kilogram-force by dividing by 9.806 65 (standard gravity). This leads to the following equation: where "F" is in N and "d" is in millimeters. A common error is that the above formula to calculate the HV number does not result in a number with