Lignum vitae wood can also be used to brew a tea. Other names for lignum vitae include palo santo (Spanish for "holy wood") Aura palo santo and "bastard greenheart" (not to be confused with true greenheart "Chlorocardium rodiei", a popular wood in shipbuilding, cabinetry, and woodturning but a completely different timber). Lignum vitae is also one of the numerous hard, dense woods loosely referred to as "ironwood". Lignum vitae is hard and durable, and is also the densest wood traded (density: 1.23 g/cm); it will easily sink in water. On the Janka Scale of Hardness, which measures hardness of woods, lignum vitae
Knoop hardness test 130 degrees for the short edge. The depth of the indentation can be approximated as 1/30 of the long dimension. The Knoop hardness "HK" or "KHN" is then given by the formula: where: HK values are typically in the range from 100 to 1000, when specified in the conventional units of kg·mm. The SI unit, pascals, are sometimes used instead: 1 kg·mm = 9.80665 MPa. The test was developed by Frederick Knoop and colleagues at the National Bureau of Standards (now NIST) of the United States in 1939, and is defined by the ASTM E384 standard. The advantages of the