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
Walter Janka called upon to testify against Janka, with the words: Wolfgang Harich had already been convicted, and sentenced to a ten-year jail term in March 1957, in respect of the same alleged conspiracy as Janka. The two had previously worked together at the Aufbau publishing house. Harich was brought into the July show-trial by as a leading prosecution witness: his testimony now heavily implicated Janka. The two former friends would remain estranged from one another for the rest of their lives. Janka served the first part of his sentence in Berlin-Hohenschönhausen prison where he had been held on remand, but in