Guaiacum uses, including as lumber, for medicinal purposes, and as ornamentals. The trade of all species of "Guaiacum" is controlled under CITES Appendix II. "Guaiacum officinale" is the national flower of Jamaica, while "Guaiacum sanctum" is the national tree of the Bahamas. The genus is famous as the supplier of lignum vitae, which is the heartwood of several species in the genus. It is the fourth-hardest variety of wood as measured by the Janka hardness test, requiring a force of to embed a steel ball in diameter half that distance into the wood. The Spanish encountered guaiacum wood when they conquered
Scratch hardness Wooddell, working at the Carborundum Company, extended the scale further by using resistance to abrasion, and extrapolating the scale based on seven for quartz and nine for corundum, resulting in a value of 42.4 for South American brown diamond bort. Resistance to abrasion is less affected by surface variations than other methods of indentations. There is a linear relationship between cohesive energy density (lattice energy per volume) and Wooddell wear resistance, occurring between corundum (H=9) and diamond (H=42.5). Scratch hardness Scratch hardness tests are used to determine the hardness of a material to scratches and abrasion. The earliest test was