boron nitride nanotubes are prepared by a process which includes : creating a source of boron vapor ; mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site , which is a surface , the nitrogen gas being provided at a pressure elevated above atmospheric , e . g ., from greater than about 2 atmospheres up to about 250 atmospheres ; and harvesting boron nitride nanotubes , which are formed at the nucleation site .