Volcanological boron compounds

I wish to present what evidence we have as to the geochemistry of boron minerals as related to volcanological processes, or, in other words, what are the volcanological boron compounds?

Volcanological processes, considered only as they apply to this question, may be grouped for present convenience as follows: (1) Extrusion of volcanic rocks; (2) volcanic exhalations including fumaroles and solfataras; (3) hot springs.